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In [[mathematics]], the '''Douady–Earle extension''', named after [[Adrien Douady]] and Clifford Earle, is a way of extending homeomorphisms of the unit circle in the complex plane to homeomorphisms of the closed unit disk, such that the extension is a diffeomorphism of the open disk. The extension is analytic on the open disk. The extension has an important equivariance property: if the homeomorphism is composed on either side with a Möbius transformation preserving the unit circle the extension is also obtained by composition with the same Möbius transformation. If the homeomorphism is [[quasisymmetric map|quasisymmetric]], the diffeomorphism is [[quasiconformal mapping|quasiconformal]]. An extension for quasisymmetric homeomorphisms had previously been given by [[Lars Ahlfors|Ahlfors]] and [[Arne Beurling]]; a different equivariant construction had been given in 1985 by Pekka Tukia. Equivariant extensions have important applications in [[Teichmüller theory]], for example they lead to a quick proof of the contractibility of the [[Teichmüller space]] of a [[Fuchsian group]].
 
==Definition==
By the [[Radó–Kneser–Choquet theorem]], the [[Poisson integral]] ''F''<sub>''f''</sub> of a homeomorphism ''f'' of the circle defines a [[harmonic function|harmonic]] diffeomorphism of the unit disk extending ''f''. If ''f'' is [[quasisymmetric map|quasisymmetric]], the extension is not necessarily quasiconformal, i.e. the complex dilatation
 
:<math>\displaystyle{\mu(z)={\partial_{\overline{z}}F_f\over \partial_z F_f},}</math>
 
does not necessarily satisfy
 
:<math>\displaystyle{\sup_{|z|<1} |\mu(z)| < 1.}</math>
 
However ''F'' can be used to define another analytic extension ''H''<sub>''f''</sub> of ''f''<sup>−1</sup> which does satisfy this condition. It follows that
 
:<math>\displaystyle{E(f)=H_{f^{-1}}}</math>
 
is the required extension.
 
For |''a''| < 1 define the Möbius transformation
 
:<math>\displaystyle{g_a(z)= {z-a\over 1- \overline{a}z}.}</math>
 
It preserves the unit circle and unit disk sending ''a'' to 0.
 
If ''g'' is any Möbius transformation preserving the unit circle and disk, then
 
:<math>\displaystyle{F_{f\circ g} = F_f\circ g.}</math>
 
For |''a''| < 1 define
 
:<math>\displaystyle{w=H_f(a)}</math>
 
to be the unique ''w'' with |''w''| < 1 and
 
:<math>\displaystyle{F_{g_a\circ f}(w) =0.}</math>
 
For |''a''| =1 set
 
:<math>\displaystyle{H_f(a)=f^{-1}(a).}</math>
 
==Properties==
*'''Compatibility with Möbius transformations.''' By construction
 
::<math>\displaystyle{H_{g\circ f \circ h} = h^{-1}\circ H_f \circ g^{-1}}</math>
 
:for any Möbius transformations ''g'' and ''h'' preserving the unit circle and disk.
 
*'''Continuity.''' If |''a''|, |''b''| < 1, define
 
::<math>\displaystyle{\Phi(a,b)= F_{g_a\circ f}(b)={1\over 2\pi}\int_0^{2\pi} g_a\circ f\circ g_{-b}(e^{i\theta})\, d\theta={1\over 2\pi}\int_0^{2\pi} \left({f(e^{i\theta}) -b\over 1-\overline{b}f(e^{i\theta})}\right) {1-|a|^2\over |a-e^{i\theta}|^2}\, d\theta}</math>
 
:If ''z''<sub>''n''</sub> and ''w''<sub>''n''</sub> lie in the unit disk and tend to ''z'' and ''w'' and homeomorphisms of the circle are defined by
 
::<math>\displaystyle{f_n=g_{z_n}\circ f \circ g_{-w_n},}</math>
 
:then ''f''<sub>''n''</sub> tends almost everywhere to
 
**''g''<sub>''z''</sub> ∘ ''f'' ∘ ''g''<sub>−''w''</sub> if |''z''|, |''w''| < 1;
**''g''<sub>''z''</sub> ∘ ''f'' (''w'') if |''z''| < 1 and |''w''| = 1;
**−''z'' if |''z''| =1 and |''w''| ≤ 1 with ''w'' ≠ ''f''<sup>−1</sup>(''z'').
 
:By the dominated convergence theorem, it follows that Φ(''z''<sub>''n''</sub>,''w''<sub>''n''</sub>) has a non-zero limit if ''w'' ≠ ''H''<sub>''f''</sub>(''z''). This implies that ''H''<sub>''f''</sub> is continuous on the closed unit disk. Indeed otherwise, by compactness, there would be a sequence ''z''<sub>''n''</sub> tending to ''z'' in the closed disk, with ''w''<sub>''n''</sub> = ''H''<sub>''f''</sub>(''z''<sub>''n''</sub>) tending to a limit ''w'' ≠ ''H''<sub>''f''</sub>(''z''). But then Φ(''z''<sub>''n''</sub>,''w''<sub>''n''</sub>) = 0 so has limit zero, a contradiction, since ''w'' ≠  ''H''<sub>''f''</sub>(''z'').
 
*'''Smoothness and non-vanishing Jacobian on open disk.''' ''H''<sub>''f''</sub> is smooth with nowhere vanishing Jacobian on |''z''| < 1. In fact, because of the compatibility with Möbius transformations, it suffices to check that ''H''<sub>''f''</sub> is smooth near 0 and has non-vanishing derivative at 0.
 
:If ''f'' has Fourier series
 
::<math>\displaystyle{f(e^{i\theta}) = \sum_m a_m e^{im\theta},}</math>
 
:then the derivatives of ''F''<sub>''f''</sub> at 0 are given by
 
::<math>\displaystyle{\partial_z F_f (0)= a_{1},\,\,\, \partial_{\overline{z}} F_f(0) =a_{-1}.}</math>
 
:Thus the Jacobian of ''F''<sub>''f''</sub> at 0 is given by
 
::<math>  \displaystyle{|\partial_z F_f(0)|^2 -  |\partial_{\overline{z}} F_f(0)|^2 = |a_{1}|^2 - |a_{-1}|^2.}</math>
 
:Since ''F''<sub>''f''</sub> is an orientation-preserving diffeomorphism, its Jacobian is positive:
 
::<math>\displaystyle{|a_{1}|^2 - |a_{-1}|^2 >0.}</math>
 
:The function Φ(''z'',''w'') is analytic and so smooth. Its derivatives at (0,0) are given by
 
::<math>\displaystyle{\Phi_z(0,0)=a_{-1},\,\,\Phi_{\overline{z}}(0,0)=a_{1},\,\, \Phi_{w}(0,0) = -1,\,\, \Phi_{\overline{w}}(0,0) = {1\over 2\pi} \int_0^{2\pi} f(e^{i\theta})^2\, d\theta=b.}</math>
 
:Direct calculation shows that
 
::<math>\displaystyle{|\Phi_{w}(0,0)|^2 - |\Phi_{\overline{w}}(0,0)|^2=1-\left|{1\over 2\pi}\int_0^{2\pi} f(e^{i\theta})^2 \, d\theta\right|^2 \ge 0.}</math>
 
:by the [[Cauchy–Schwarz inequality]]. If the right hand side vanished, then equality would occur in the Cauchy-Schwarz inequality forcing
 
::<math>\displaystyle{f(e^{i\theta}) =\zeta \overline{f(e^{i\theta})}}</math>
 
:for some ζ in '''T''' and for all θ, a contradiction since ''f'' assumes all values in '''T'''. The left hand side is therefore strictly positive and |''b''| < 1.
 
:Consequently the [[implicit function theorem]] can be applied. It implies that ''H''<sub>''f''</sub>(''z'') is smooth near o. Its  Jacobian can be computed by implicit differentiation:
 
::<math>\displaystyle{|\partial_z H_f(0)|^2 -  |\partial_{\overline{z}}H_f(0)|^2 = {|\Phi_z(0,0)|^2 - |\Phi_{\overline{z}}(0,0)|^2 \over |\Phi_w(0,0)|^2 -|\Phi_{\overline{w}}(0,0)|^2} >0.}</math>
 
:Moreover
 
::<math>\displaystyle{{\partial_{\overline{z}}H_f (0)\over \partial_{z} H_f(0)}=g_b\left(-{a_{-1}\over \overline{a_{1}}}\right).}</math>
 
*'''Homeomorphism on closed disk and diffeomorphism on open disk.''' It is enough to show that ''H''<sub>''f''</sub> is a homeomorphism. By continuity its image is compact so closed. The non-vanishing of the Jacobian, implies that ''H''<sub>''f''</sub> is an open mapping on the unit disk, so that the image of the open disk is open. Hence the image of the closed disk is an open and closed subset of the closed disk. By connectivity, it must be the whole disk. For |''w''| < 1, the inverse image of ''w'' is closed, so compact, and entirely contained in the open disk. Since ''H''<sub>''f''</sub> is locally a homeomorphism, it must be a finite set. The set of points ''w'' in the open disk with exactly ''n'' preimages is open. By connectivity every point has the same number ''N'' of preimages. Since the open disk is [[simply connected]], ''N'' = 1. (In fact taking any preimage of the origin, every radial line has a unique lifting to a preimage, and so there is an open subset of the unit disk mapping homeomorphically onto the open disc. If ''N'' > 1, its complement would also have to be open, contradicting connectivity.)
 
==Extension of quasi-Möbius homeomorphisms==
In this section it is established that the extension of a [[quasisymmetric map|quasisymmetric]] homeomorphism is [[quasiconformal mapping|quasiconformal]]. Fundamental use is made of the notion of '''quasi-Möbius homeomorphism'''.
 
A homeomorphism ''f'' of the circle is [[quasisymmetric map|''quasisymmetric'']] if there are constants ''a'', ''b'' > 0 such that
 
:<math>\displaystyle{{|f(z_1)-f(z_2)|\over |f(z_1)-f(z_3)|} \le a {|z_1-z_2|^b\over |z_1-z_3|^b}.}</math>
 
It is ''quasi-Möbius'' is there are constants ''c'', ''d'' > 0 such that
 
:<math>\displaystyle{|(f(z_1),f(z_2);f(z_3),f(z_4))| \le c |(z_1,z_2;z_3,z_4)|^d,}</math>
 
where
 
:<math>\displaystyle{ (z_1,z_2;z_3,z_4)={(z_1-z_3)(z_2-z_4)\over(z_2-z_3)(z_1-z_4)}}</math>
 
denotes the [[cross-ratio]].
 
If ''f'' is quasisymmetric then it is also quasi-Möbius, with ''c'' = ''a''<sup>2</sup> and ''d'' = ''b'': this follows by multiplying the first inequality for (''z''<sub>1</sub>,''z''<sub>3</sub>,''z''<sub>4</sub>) and (''z''<sub>2</sub>,''z''<sub>4</sub>,''z''<sub>3</sub>). (Conversely {{harvtxt|Väisäläa|1985}} has shown that a quasi-Möbius homeomorphism is also quasisymmetric.)
 
It is immediate that the quasi-Möbius homeomorphisms are closed under the operations of inversion and composition.
 
The [[Beltrami equation|complex dilatation]] μ of a diffeomorphism ''F'' of the unit disk is defined by
 
:<math>\displaystyle{\mu_F(z)={\partial_{\overline{z}}F(z)\over \partial_z F(z)}.}</math>
 
If ''F'' and ''G'' are diffeomorphisms of the disk, then
 
:<math>\displaystyle{\mu_{G\circ F^{-1}}\circ F={F_z\over \overline{F_z}} {\mu_G-\mu_F\over 1 -\overline{\mu_F}\mu_G}.}</math>
 
In particular if ''G'' is holomorphic, then
 
:<math>\displaystyle{\mu_{F\circ G^{-1}} \circ G = {G_z\over \overline{G_z}} \mu_F,\,\,\, \mu_{G^{-1}\circ F}=\mu_F.}</math>
 
When ''F'' = ''H''<sub>''f''</sub>,
 
:<math>\displaystyle{\mu_F(0)=g_b\left( -{a_{-1}\over \overline{a_{1}}}\right),}</math>
 
where
 
:<math>\displaystyle{a_{\pm 1}={1\over 2\pi} \int_0^{2\pi} f(e^{i\theta})e^{\mp i\theta} \, d\theta,\,\,\, b={1\over 2\pi} \int_0^{2\pi} f(e^{i\theta})^2 \, d\theta.}</math>
 
To prove that ''F'' = ''H''<sub>''f''</sub> is quasiconformal amounts to showing that
 
:<math>\displaystyle{\|\mu_F\|_\infty < 1.}</math>
 
Since ''f'' ia a quasi-Möbius homeomorphism the compositions ''g''<sub>1</sub> ∘ ''f'' ∘ ''g''<sub>2</sub> with ''g''<sub>''i''</sub> Möbius transformations satisfy exactly the same estimates, since Möbius transformations preserve the cross ratio. So to prove that ''H''<sub>''f''</sub> is quasiconformal it suffices to show that if ''f'' is any quasi-Möbius homeomorphism fixing 1, ''i'' and −''i'', with fixed ''c'' and ''d'', then the quantities
 
:<math>\displaystyle{\Lambda(f)=\left|g_b\left( -{a_{-1}\over \overline{a_{1}}}\right)\right|}</math>
 
have an upper bound strictly less than one.
 
On the other hand if ''f'' is quasi-Möbius and fixes 1, ''i'' and −''i'', then ''f'' satisfies a [[Hölder continuity]] condition:
 
:<math>\displaystyle{|f(z)-f(w)|\le C |z-w|^d,}</math>
 
for another positive constant ''C'' independent of ''f''. The same is true for the ''f''<sup>−1</sup>'s. But then the [[Arzelà–Ascoli theorem]] implies these homeomorphisms form a compact subset in C('''T'''). The non-linear functional Λ is continuous on this subset and therefore attains its upper bound at some ''f''<sub>0</sub>. On the other hand Λ(''f''<sub>0</sub>) < 1, so the upper bound is strictly less than 1.
 
The uniform Hölder estimate for ''f'' is established in {{harvtxt|Väisäläa|1985}} as follows. Take ''z'', ''w'' in '''T'''.
 
*If |''z'' − 1| ≤ 1/4 and |''z'' - ''w''| ≤ 1/8, then |''z'' ± ''i''| ≥ 1/4 and |''w'' ± ''i''| ≥ 1/8. But then
 
::<math>\displaystyle{|(w,i; z,-i)| \le 16|z-w|,\,\,\, |(f(w),i; f(z),-i)| \ge  |f(z)-f(w)|/8,}</math>
 
:so there is a corresponding Hölder estimate.
 
*If |''z'' - ''w''| ≥ 1/8, the Hölder estimate is trivial since |''f''(''z'') - ''f''(''w'')| ≤ 2.
 
*If |''z'' - 1| ≥ 1/4, then |''w'' - ζ| ≥ 1/4 for ζ = ''i'' or −''i''. But then
 
::<math>\displaystyle{ |(z,\zeta;w,1)| \le 8|z-w|,\,\,\, |(f(z),\zeta; f(w),1)|\ge  |f(z)-f(w)|/8,}</math>
 
:so there is a corresponding Hölder estimate.
 
==References==
*{{citation|last=Douady|first= Adrien|author1-link=Adrien Douady|last2= Earle|first2 =Clifford J.|title=Conformally natural extension of homeomorphisms of the circle|journal=Acta Math.|volume= 157|year=1986|pages=23–48}}
*{{citation|last=Kapovich|first= Michael|title= Hyperbolic manifolds and discrete groups|series= Progress in Mathematics|volume= 183| publisher=Birkhäuser|year= 2001|isbn=0-8176-3904-7}}
*{{citation|last=Partyka|first= Dariusz|title=The generalized Neumann-Poincaré operator and its spectrum|series=
Dissertationes Math|volume= 366|year=1997}}
*{{citation|last=Partyka|first=Dariusz|last2= Sakan|first2= Ken-Ichi|last3= Zając|first3= Józef|title=The harmonic and quasiconformal extension operators|pages= 141–177|journal=Banach Center Publ.|volume= 48|year= 1999}}
*{{citation|last=Väisälä|first= Jussi|title=Quasi-Möbius maps|journal=J. Analyse Math. |volume=44|year=1985|pages= 218–234}}
 
{{DEFAULTSORT:Douady-Earle extension}}
[[Category:Complex analysis]]

Revision as of 03:08, 30 January 2014

In mathematics, the Douady–Earle extension, named after Adrien Douady and Clifford Earle, is a way of extending homeomorphisms of the unit circle in the complex plane to homeomorphisms of the closed unit disk, such that the extension is a diffeomorphism of the open disk. The extension is analytic on the open disk. The extension has an important equivariance property: if the homeomorphism is composed on either side with a Möbius transformation preserving the unit circle the extension is also obtained by composition with the same Möbius transformation. If the homeomorphism is quasisymmetric, the diffeomorphism is quasiconformal. An extension for quasisymmetric homeomorphisms had previously been given by Ahlfors and Arne Beurling; a different equivariant construction had been given in 1985 by Pekka Tukia. Equivariant extensions have important applications in Teichmüller theory, for example they lead to a quick proof of the contractibility of the Teichmüller space of a Fuchsian group.

Definition

By the Radó–Kneser–Choquet theorem, the Poisson integral Ff of a homeomorphism f of the circle defines a harmonic diffeomorphism of the unit disk extending f. If f is quasisymmetric, the extension is not necessarily quasiconformal, i.e. the complex dilatation

μ(z)=zFfzFf,

does not necessarily satisfy

sup|z|<1|μ(z)|<1.

However F can be used to define another analytic extension Hf of f−1 which does satisfy this condition. It follows that

E(f)=Hf1

is the required extension.

For |a| < 1 define the Möbius transformation

ga(z)=za1az.

It preserves the unit circle and unit disk sending a to 0.

If g is any Möbius transformation preserving the unit circle and disk, then

Ffg=Ffg.

For |a| < 1 define

w=Hf(a)

to be the unique w with |w| < 1 and

Fgaf(w)=0.

For |a| =1 set

Hf(a)=f1(a).

Properties

  • Compatibility with Möbius transformations. By construction
Hgfh=h1Hfg1
for any Möbius transformations g and h preserving the unit circle and disk.
  • Continuity. If |a|, |b| < 1, define
Φ(a,b)=Fgaf(b)=12π02πgafgb(eiθ)dθ=12π02π(f(eiθ)b1bf(eiθ))1|a|2|aeiθ|2dθ
If zn and wn lie in the unit disk and tend to z and w and homeomorphisms of the circle are defined by
fn=gznfgwn,
then fn tends almost everywhere to
    • gzfgw if |z|, |w| < 1;
    • gzf (w) if |z| < 1 and |w| = 1;
    • z if |z| =1 and |w| ≤ 1 with wf−1(z).
By the dominated convergence theorem, it follows that Φ(zn,wn) has a non-zero limit if wHf(z). This implies that Hf is continuous on the closed unit disk. Indeed otherwise, by compactness, there would be a sequence zn tending to z in the closed disk, with wn = Hf(zn) tending to a limit wHf(z). But then Φ(zn,wn) = 0 so has limit zero, a contradiction, since wHf(z).
  • Smoothness and non-vanishing Jacobian on open disk. Hf is smooth with nowhere vanishing Jacobian on |z| < 1. In fact, because of the compatibility with Möbius transformations, it suffices to check that Hf is smooth near 0 and has non-vanishing derivative at 0.
If f has Fourier series
f(eiθ)=mameimθ,
then the derivatives of Ff at 0 are given by
zFf(0)=a1,zFf(0)=a1.
Thus the Jacobian of Ff at 0 is given by
|zFf(0)|2|zFf(0)|2=|a1|2|a1|2.
Since Ff is an orientation-preserving diffeomorphism, its Jacobian is positive:
|a1|2|a1|2>0.
The function Φ(z,w) is analytic and so smooth. Its derivatives at (0,0) are given by
Φz(0,0)=a1,Φz(0,0)=a1,Φw(0,0)=1,Φw(0,0)=12π02πf(eiθ)2dθ=b.
Direct calculation shows that
|Φw(0,0)|2|Φw(0,0)|2=1|12π02πf(eiθ)2dθ|20.
by the Cauchy–Schwarz inequality. If the right hand side vanished, then equality would occur in the Cauchy-Schwarz inequality forcing
f(eiθ)=ζf(eiθ)
for some ζ in T and for all θ, a contradiction since f assumes all values in T. The left hand side is therefore strictly positive and |b| < 1.
Consequently the implicit function theorem can be applied. It implies that Hf(z) is smooth near o. Its Jacobian can be computed by implicit differentiation:
|zHf(0)|2|zHf(0)|2=|Φz(0,0)|2|Φz(0,0)|2|Φw(0,0)|2|Φw(0,0)|2>0.
Moreover
zHf(0)zHf(0)=gb(a1a1).
  • Homeomorphism on closed disk and diffeomorphism on open disk. It is enough to show that Hf is a homeomorphism. By continuity its image is compact so closed. The non-vanishing of the Jacobian, implies that Hf is an open mapping on the unit disk, so that the image of the open disk is open. Hence the image of the closed disk is an open and closed subset of the closed disk. By connectivity, it must be the whole disk. For |w| < 1, the inverse image of w is closed, so compact, and entirely contained in the open disk. Since Hf is locally a homeomorphism, it must be a finite set. The set of points w in the open disk with exactly n preimages is open. By connectivity every point has the same number N of preimages. Since the open disk is simply connected, N = 1. (In fact taking any preimage of the origin, every radial line has a unique lifting to a preimage, and so there is an open subset of the unit disk mapping homeomorphically onto the open disc. If N > 1, its complement would also have to be open, contradicting connectivity.)

Extension of quasi-Möbius homeomorphisms

In this section it is established that the extension of a quasisymmetric homeomorphism is quasiconformal. Fundamental use is made of the notion of quasi-Möbius homeomorphism.

A homeomorphism f of the circle is quasisymmetric if there are constants a, b > 0 such that

|f(z1)f(z2)||f(z1)f(z3)|a|z1z2|b|z1z3|b.

It is quasi-Möbius is there are constants c, d > 0 such that

|(f(z1),f(z2);f(z3),f(z4))|c|(z1,z2;z3,z4)|d,

where

(z1,z2;z3,z4)=(z1z3)(z2z4)(z2z3)(z1z4)

denotes the cross-ratio.

If f is quasisymmetric then it is also quasi-Möbius, with c = a2 and d = b: this follows by multiplying the first inequality for (z1,z3,z4) and (z2,z4,z3). (Conversely Template:Harvtxt has shown that a quasi-Möbius homeomorphism is also quasisymmetric.)

It is immediate that the quasi-Möbius homeomorphisms are closed under the operations of inversion and composition.

The complex dilatation μ of a diffeomorphism F of the unit disk is defined by

μF(z)=zF(z)zF(z).

If F and G are diffeomorphisms of the disk, then

μGF1F=FzFzμGμF1μFμG.

In particular if G is holomorphic, then

μFG1G=GzGzμF,μG1F=μF.

When F = Hf,

μF(0)=gb(a1a1),

where

a±1=12π02πf(eiθ)eiθdθ,b=12π02πf(eiθ)2dθ.

To prove that F = Hf is quasiconformal amounts to showing that

μF<1.

Since f ia a quasi-Möbius homeomorphism the compositions g1fg2 with gi Möbius transformations satisfy exactly the same estimates, since Möbius transformations preserve the cross ratio. So to prove that Hf is quasiconformal it suffices to show that if f is any quasi-Möbius homeomorphism fixing 1, i and −i, with fixed c and d, then the quantities

Λ(f)=|gb(a1a1)|

have an upper bound strictly less than one.

On the other hand if f is quasi-Möbius and fixes 1, i and −i, then f satisfies a Hölder continuity condition:

|f(z)f(w)|C|zw|d,

for another positive constant C independent of f. The same is true for the f−1's. But then the Arzelà–Ascoli theorem implies these homeomorphisms form a compact subset in C(T). The non-linear functional Λ is continuous on this subset and therefore attains its upper bound at some f0. On the other hand Λ(f0) < 1, so the upper bound is strictly less than 1.

The uniform Hölder estimate for f is established in Template:Harvtxt as follows. Take z, w in T.

  • If |z − 1| ≤ 1/4 and |z - w| ≤ 1/8, then |z ± i| ≥ 1/4 and |w ± i| ≥ 1/8. But then
|(w,i;z,i)|16|zw|,|(f(w),i;f(z),i)||f(z)f(w)|/8,
so there is a corresponding Hölder estimate.
  • If |z - w| ≥ 1/8, the Hölder estimate is trivial since |f(z) - f(w)| ≤ 2.
  • If |z - 1| ≥ 1/4, then |w - ζ| ≥ 1/4 for ζ = i or −i. But then
|(z,ζ;w,1)|8|zw|,|(f(z),ζ;f(w),1)||f(z)f(w)|/8,
so there is a corresponding Hölder estimate.

References

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    Naturally, you will have to pay a safety deposit and that is usually one month rent for annually of the settlement. That is the place your good religion deposit will likely be taken into account and will kind part or all of your security deposit. Anticipate to have a proportionate amount deducted out of your deposit if something is discovered to be damaged if you move out. It's best to you'll want to test the inventory drawn up by the owner, which can detail all objects in the property and their condition. If you happen to fail to notice any harm not already mentioned within the inventory before transferring in, you danger having to pay for it yourself.

    In case you are in search of an actual estate or Singapore property agent on-line, you simply should belief your intuition. It's because you do not know which agent is nice and which agent will not be. Carry out research on several brokers by looking out the internet. As soon as if you end up positive that a selected agent is dependable and reliable, you can choose to utilize his partnerise in finding you a home in Singapore. Most of the time, a property agent is taken into account to be good if he or she locations the contact data on his website. This may mean that the agent does not mind you calling them and asking them any questions relating to new properties in singapore in Singapore. After chatting with them you too can see them in their office after taking an appointment.

    Have handed an trade examination i.e Widespread Examination for House Brokers (CEHA) or Actual Property Agency (REA) examination, or equal; Exclusive brokers are extra keen to share listing information thus making certain the widest doable coverage inside the real estate community via Multiple Listings and Networking. Accepting a severe provide is simpler since your agent is totally conscious of all advertising activity related with your property. This reduces your having to check with a number of agents for some other offers. Price control is easily achieved. Paint work in good restore-discuss with your Property Marketing consultant if main works are still to be done. Softening in residential property prices proceed, led by 2.8 per cent decline within the index for Remainder of Central Region

    Once you place down the one per cent choice price to carry down a non-public property, it's important to accept its situation as it is whenever you move in – faulty air-con, choked rest room and all. Get round this by asking your agent to incorporate a ultimate inspection clause within the possibility-to-buy letter. HDB flat patrons routinely take pleasure in this security net. "There's a ultimate inspection of the property two days before the completion of all HDB transactions. If the air-con is defective, you can request the seller to repair it," says Kelvin.

    15.6.1 As the agent is an intermediary, generally, as soon as the principal and third party are introduced right into a contractual relationship, the agent drops out of the image, subject to any problems with remuneration or indemnification that he could have against the principal, and extra exceptionally, against the third occasion. Generally, agents are entitled to be indemnified for all liabilities reasonably incurred within the execution of the brokers´ authority.

    To achieve the very best outcomes, you must be always updated on market situations, including past transaction information and reliable projections. You could review and examine comparable homes that are currently available in the market, especially these which have been sold or not bought up to now six months. You'll be able to see a pattern of such report by clicking here It's essential to defend yourself in opposition to unscrupulous patrons. They are often very skilled in using highly unethical and manipulative techniques to try and lure you into a lure. That you must also protect your self, your loved ones, and personal belongings as you'll be serving many strangers in your home. Sign a listing itemizing of all of the objects provided by the proprietor, together with their situation. HSR Prime Recruiter 2010
  • Many property agents need to declare for the PIC grant in Singapore. However, not all of them know find out how to do the correct process for getting this PIC scheme from the IRAS. There are a number of steps that you need to do before your software can be approved.

    Naturally, you will have to pay a safety deposit and that is usually one month rent for annually of the settlement. That is the place your good religion deposit will likely be taken into account and will kind part or all of your security deposit. Anticipate to have a proportionate amount deducted out of your deposit if something is discovered to be damaged if you move out. It's best to you'll want to test the inventory drawn up by the owner, which can detail all objects in the property and their condition. If you happen to fail to notice any harm not already mentioned within the inventory before transferring in, you danger having to pay for it yourself.

    In case you are in search of an actual estate or Singapore property agent on-line, you simply should belief your intuition. It's because you do not know which agent is nice and which agent will not be. Carry out research on several brokers by looking out the internet. As soon as if you end up positive that a selected agent is dependable and reliable, you can choose to utilize his partnerise in finding you a home in Singapore. Most of the time, a property agent is taken into account to be good if he or she locations the contact data on his website. This may mean that the agent does not mind you calling them and asking them any questions relating to new properties in singapore in Singapore. After chatting with them you too can see them in their office after taking an appointment.

    Have handed an trade examination i.e Widespread Examination for House Brokers (CEHA) or Actual Property Agency (REA) examination, or equal; Exclusive brokers are extra keen to share listing information thus making certain the widest doable coverage inside the real estate community via Multiple Listings and Networking. Accepting a severe provide is simpler since your agent is totally conscious of all advertising activity related with your property. This reduces your having to check with a number of agents for some other offers. Price control is easily achieved. Paint work in good restore-discuss with your Property Marketing consultant if main works are still to be done. Softening in residential property prices proceed, led by 2.8 per cent decline within the index for Remainder of Central Region

    Once you place down the one per cent choice price to carry down a non-public property, it's important to accept its situation as it is whenever you move in – faulty air-con, choked rest room and all. Get round this by asking your agent to incorporate a ultimate inspection clause within the possibility-to-buy letter. HDB flat patrons routinely take pleasure in this security net. "There's a ultimate inspection of the property two days before the completion of all HDB transactions. If the air-con is defective, you can request the seller to repair it," says Kelvin.

    15.6.1 As the agent is an intermediary, generally, as soon as the principal and third party are introduced right into a contractual relationship, the agent drops out of the image, subject to any problems with remuneration or indemnification that he could have against the principal, and extra exceptionally, against the third occasion. Generally, agents are entitled to be indemnified for all liabilities reasonably incurred within the execution of the brokers´ authority.

    To achieve the very best outcomes, you must be always updated on market situations, including past transaction information and reliable projections. You could review and examine comparable homes that are currently available in the market, especially these which have been sold or not bought up to now six months. You'll be able to see a pattern of such report by clicking here It's essential to defend yourself in opposition to unscrupulous patrons. They are often very skilled in using highly unethical and manipulative techniques to try and lure you into a lure. That you must also protect your self, your loved ones, and personal belongings as you'll be serving many strangers in your home. Sign a listing itemizing of all of the objects provided by the proprietor, together with their situation. HSR Prime Recruiter 2010
  • Many property agents need to declare for the PIC grant in Singapore. However, not all of them know find out how to do the correct process for getting this PIC scheme from the IRAS. There are a number of steps that you need to do before your software can be approved.

    Naturally, you will have to pay a safety deposit and that is usually one month rent for annually of the settlement. That is the place your good religion deposit will likely be taken into account and will kind part or all of your security deposit. Anticipate to have a proportionate amount deducted out of your deposit if something is discovered to be damaged if you move out. It's best to you'll want to test the inventory drawn up by the owner, which can detail all objects in the property and their condition. If you happen to fail to notice any harm not already mentioned within the inventory before transferring in, you danger having to pay for it yourself.

    In case you are in search of an actual estate or Singapore property agent on-line, you simply should belief your intuition. It's because you do not know which agent is nice and which agent will not be. Carry out research on several brokers by looking out the internet. As soon as if you end up positive that a selected agent is dependable and reliable, you can choose to utilize his partnerise in finding you a home in Singapore. Most of the time, a property agent is taken into account to be good if he or she locations the contact data on his website. This may mean that the agent does not mind you calling them and asking them any questions relating to new properties in singapore in Singapore. After chatting with them you too can see them in their office after taking an appointment.

    Have handed an trade examination i.e Widespread Examination for House Brokers (CEHA) or Actual Property Agency (REA) examination, or equal; Exclusive brokers are extra keen to share listing information thus making certain the widest doable coverage inside the real estate community via Multiple Listings and Networking. Accepting a severe provide is simpler since your agent is totally conscious of all advertising activity related with your property. This reduces your having to check with a number of agents for some other offers. Price control is easily achieved. Paint work in good restore-discuss with your Property Marketing consultant if main works are still to be done. Softening in residential property prices proceed, led by 2.8 per cent decline within the index for Remainder of Central Region

    Once you place down the one per cent choice price to carry down a non-public property, it's important to accept its situation as it is whenever you move in – faulty air-con, choked rest room and all. Get round this by asking your agent to incorporate a ultimate inspection clause within the possibility-to-buy letter. HDB flat patrons routinely take pleasure in this security net. "There's a ultimate inspection of the property two days before the completion of all HDB transactions. If the air-con is defective, you can request the seller to repair it," says Kelvin.

    15.6.1 As the agent is an intermediary, generally, as soon as the principal and third party are introduced right into a contractual relationship, the agent drops out of the image, subject to any problems with remuneration or indemnification that he could have against the principal, and extra exceptionally, against the third occasion. Generally, agents are entitled to be indemnified for all liabilities reasonably incurred within the execution of the brokers´ authority.

    To achieve the very best outcomes, you must be always updated on market situations, including past transaction information and reliable projections. You could review and examine comparable homes that are currently available in the market, especially these which have been sold or not bought up to now six months. You'll be able to see a pattern of such report by clicking here It's essential to defend yourself in opposition to unscrupulous patrons. They are often very skilled in using highly unethical and manipulative techniques to try and lure you into a lure. That you must also protect your self, your loved ones, and personal belongings as you'll be serving many strangers in your home. Sign a listing itemizing of all of the objects provided by the proprietor, together with their situation. HSR Prime Recruiter 2010
  • Many property agents need to declare for the PIC grant in Singapore. However, not all of them know find out how to do the correct process for getting this PIC scheme from the IRAS. There are a number of steps that you need to do before your software can be approved.

    Naturally, you will have to pay a safety deposit and that is usually one month rent for annually of the settlement. That is the place your good religion deposit will likely be taken into account and will kind part or all of your security deposit. Anticipate to have a proportionate amount deducted out of your deposit if something is discovered to be damaged if you move out. It's best to you'll want to test the inventory drawn up by the owner, which can detail all objects in the property and their condition. If you happen to fail to notice any harm not already mentioned within the inventory before transferring in, you danger having to pay for it yourself.

    In case you are in search of an actual estate or Singapore property agent on-line, you simply should belief your intuition. It's because you do not know which agent is nice and which agent will not be. Carry out research on several brokers by looking out the internet. As soon as if you end up positive that a selected agent is dependable and reliable, you can choose to utilize his partnerise in finding you a home in Singapore. Most of the time, a property agent is taken into account to be good if he or she locations the contact data on his website. This may mean that the agent does not mind you calling them and asking them any questions relating to new properties in singapore in Singapore. After chatting with them you too can see them in their office after taking an appointment.

    Have handed an trade examination i.e Widespread Examination for House Brokers (CEHA) or Actual Property Agency (REA) examination, or equal; Exclusive brokers are extra keen to share listing information thus making certain the widest doable coverage inside the real estate community via Multiple Listings and Networking. Accepting a severe provide is simpler since your agent is totally conscious of all advertising activity related with your property. This reduces your having to check with a number of agents for some other offers. Price control is easily achieved. Paint work in good restore-discuss with your Property Marketing consultant if main works are still to be done. Softening in residential property prices proceed, led by 2.8 per cent decline within the index for Remainder of Central Region

    Once you place down the one per cent choice price to carry down a non-public property, it's important to accept its situation as it is whenever you move in – faulty air-con, choked rest room and all. Get round this by asking your agent to incorporate a ultimate inspection clause within the possibility-to-buy letter. HDB flat patrons routinely take pleasure in this security net. "There's a ultimate inspection of the property two days before the completion of all HDB transactions. If the air-con is defective, you can request the seller to repair it," says Kelvin.

    15.6.1 As the agent is an intermediary, generally, as soon as the principal and third party are introduced right into a contractual relationship, the agent drops out of the image, subject to any problems with remuneration or indemnification that he could have against the principal, and extra exceptionally, against the third occasion. Generally, agents are entitled to be indemnified for all liabilities reasonably incurred within the execution of the brokers´ authority.

    To achieve the very best outcomes, you must be always updated on market situations, including past transaction information and reliable projections. You could review and examine comparable homes that are currently available in the market, especially these which have been sold or not bought up to now six months. You'll be able to see a pattern of such report by clicking here It's essential to defend yourself in opposition to unscrupulous patrons. They are often very skilled in using highly unethical and manipulative techniques to try and lure you into a lure. That you must also protect your self, your loved ones, and personal belongings as you'll be serving many strangers in your home. Sign a listing itemizing of all of the objects provided by the proprietor, together with their situation. HSR Prime Recruiter 2010
  • Many property agents need to declare for the PIC grant in Singapore. However, not all of them know find out how to do the correct process for getting this PIC scheme from the IRAS. There are a number of steps that you need to do before your software can be approved.

    Naturally, you will have to pay a safety deposit and that is usually one month rent for annually of the settlement. That is the place your good religion deposit will likely be taken into account and will kind part or all of your security deposit. Anticipate to have a proportionate amount deducted out of your deposit if something is discovered to be damaged if you move out. It's best to you'll want to test the inventory drawn up by the owner, which can detail all objects in the property and their condition. If you happen to fail to notice any harm not already mentioned within the inventory before transferring in, you danger having to pay for it yourself.

    In case you are in search of an actual estate or Singapore property agent on-line, you simply should belief your intuition. It's because you do not know which agent is nice and which agent will not be. Carry out research on several brokers by looking out the internet. As soon as if you end up positive that a selected agent is dependable and reliable, you can choose to utilize his partnerise in finding you a home in Singapore. Most of the time, a property agent is taken into account to be good if he or she locations the contact data on his website. This may mean that the agent does not mind you calling them and asking them any questions relating to new properties in singapore in Singapore. After chatting with them you too can see them in their office after taking an appointment.

    Have handed an trade examination i.e Widespread Examination for House Brokers (CEHA) or Actual Property Agency (REA) examination, or equal; Exclusive brokers are extra keen to share listing information thus making certain the widest doable coverage inside the real estate community via Multiple Listings and Networking. Accepting a severe provide is simpler since your agent is totally conscious of all advertising activity related with your property. This reduces your having to check with a number of agents for some other offers. Price control is easily achieved. Paint work in good restore-discuss with your Property Marketing consultant if main works are still to be done. Softening in residential property prices proceed, led by 2.8 per cent decline within the index for Remainder of Central Region

    Once you place down the one per cent choice price to carry down a non-public property, it's important to accept its situation as it is whenever you move in – faulty air-con, choked rest room and all. Get round this by asking your agent to incorporate a ultimate inspection clause within the possibility-to-buy letter. HDB flat patrons routinely take pleasure in this security net. "There's a ultimate inspection of the property two days before the completion of all HDB transactions. If the air-con is defective, you can request the seller to repair it," says Kelvin.

    15.6.1 As the agent is an intermediary, generally, as soon as the principal and third party are introduced right into a contractual relationship, the agent drops out of the image, subject to any problems with remuneration or indemnification that he could have against the principal, and extra exceptionally, against the third occasion. Generally, agents are entitled to be indemnified for all liabilities reasonably incurred within the execution of the brokers´ authority.

    To achieve the very best outcomes, you must be always updated on market situations, including past transaction information and reliable projections. You could review and examine comparable homes that are currently available in the market, especially these which have been sold or not bought up to now six months. You'll be able to see a pattern of such report by clicking here It's essential to defend yourself in opposition to unscrupulous patrons. They are often very skilled in using highly unethical and manipulative techniques to try and lure you into a lure. That you must also protect your self, your loved ones, and personal belongings as you'll be serving many strangers in your home. Sign a listing itemizing of all of the objects provided by the proprietor, together with their situation. HSR Prime Recruiter 2010