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| In [[mathematics]], the '''Butcher group''', named after the New Zealand mathematician [[John C. Butcher]] by {{harvtxt|Hairer|Wanner|1974}}, is an infinite-dimensional [[group (mathematics)|group]] first introduced in [[numerical analysis]] to study solutions of non-linear [[ordinary differential equation]]s by the [[Runge–Kutta method]]. It arose from an algebraic formalism involving [[rooted tree]]s that provides [[formal power series]] solutions of the differential equation modeling the flow of a [[vector field]]. It was {{harvtxt|Cayley|1857}}, prompted by the work of [[James Joseph Sylvester|Sylvester]] on change of variables in [[differential calculus]], who first noted that the [[Faà di Bruno's formula|derivatives of a composition of functions]] can be conveniently expressed in terms of rooted trees and their combinatorics.
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| {{harvtxt|Connes|Kreimer|1999}} pointed out that the Butcher group is the group of characters of the [[Hopf algebra]] of rooted trees that had arisen independently in their own work on [[renormalization]] in [[quantum field theory]] and [[Alain Connes|Connes]]' work with [[Henri Moscovici|Moscovici]] on local [[index theorem]]s. This Hopf algebra, often called the ''Connes-Kreimer algebra'', is essentially equivalent to the Butcher group, since its dual can be identified with the [[universal enveloping algebra]] of the [[Lie algebra]] of the Butcher group.<ref>{{harvnb|Brouder|2004}}</ref> As they commented:
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| {{cquote|We regard Butcher’s work on the classification of numerical integration methods as an impressive example that concrete problem-oriented work can lead to far-reaching conceptual results.}}
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| ==Differentials and rooted trees==
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| [[File:Caylrich-first-trees.png|thumb|250px|right|Rooted trees with two, three and four nodes, from Cayley's original article]]
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| A rooted tree is a [[graph theory|graph]] with a distinguished node, called the ''root'', in which every other node is connected to the root by a unique path. If the root of a tree '''t''' is removed and the nodes connected to the original node by a single bond are taken as new roots, the tree '''t''' breaks up into rooted trees '''t'''<sub>1</sub>, '''t'''<sub>2</sub>, ... Reversing this process a new tree '''t''' = ['''t'''<sub>1</sub>, '''t'''<sub>2</sub>, ...] can be constructed by joining the roots of the trees to a new common root. The number of nodes in a tree is denoted by |'''t'''|. A ''heap-ordering'' of a rooted tree '''t''' is an allocation of the numbers 1 through |'''t'''| to the nodes so that the numbers increase on any path going away from the root. Two heap orderings are ''equivalent'', if there is an [[automorphism]] of rooted trees mapping one of them on the other. The number of [[equivalence class]]es of heap-orderings on a particular tree is denoted by α('''t''') and can be computed using the Butcher's formula:<ref name="Butcher2008">{{harvnb|Butcher|2008}}</ref><ref>{{harvnb|Brouder|2000}}</ref>
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| :<math>\displaystyle \alpha(t)= {|t|!\over t! |S_t|},</math>
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| where ''S''<sub>'''t'''</sub> denotes the [[symmetry group]] of '''t''' and the tree factorial is defined recursively by
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| :<math>[t_1,\dots,t_n]! = |[t_1,\dots,t_n]| \cdot t_1! \cdots t_n!</math>
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| with the tree factorial of an isolated root defined to be 1
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| :<math>\bullet ! =1.</math>
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| The ordinary differential equation for the flow of a [[vector field]] on an open subset ''U'' of '''R'''<sup>N</sup> can be written
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| :<math>\displaystyle {dx(s)\over ds} = f(x(s)),\,\, x(0)=x_0, </math>
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| where ''x''(''s'') takes values in ''U'', ''f'' is a smooth function from ''U'' to '''R'''<sup>N</sup> and ''x''<sub>0</sub> is the starting point of the flow at time ''s'' = 0.
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| {{harvtxt|Cayley|1857}} gave a method to compute the higher order derivatives ''x''<sup>(''m'')</sup>(''s'') in terms of rooted trees. His formula can be conveniently expressed using the ''elementary differentials'' introduced by Butcher. These are defined inductively by
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| :<math> \delta_\bullet^i= f^i, \,\,\, \delta^i_{[t_1,\dots,t_n]} = \sum_{j_1,\dots,j_n=1}^N (\delta^{j_1}_{t_1} \cdots \delta^{j_n}_{t_n})\partial_{j_1} \cdots \partial_{j_n} f^i.</math>
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| With this notation
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| :<math> {d^m x\over ds^m} = \sum_{|t|=m} \alpha(t) \delta_t,</math>
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| giving the power series expansion
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| :<math>\displaystyle x(s) = x_0 + \sum_{t} {s^{|t|}\over |t|!} \alpha(t) \delta_t(0).</math>
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| As an example when ''N'' = 1, so that ''x'' and ''f'' are real-valued functions of a single real variable, the formula yields
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| :<math> x^{(4)} = f^{\prime\prime\prime}f^3 + 3 f^{\prime\prime}f^{\prime} f^2 + f^{\prime}f^{\prime\prime} f^2 +(f^\prime)^3 f,</math>
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| where the four terms correspond to the four rooted trees from left to right in Figure 3 above.
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| In a single variable this formula is the same as [[Faà di Bruno's formula]] of 1855; however in several variables it has to be written more carefully in the form
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| :<math> x^{(4)} = f^{\prime\prime\prime}(f,f,f) + 3f^{\prime\prime}(f,f^\prime(f)) + f^\prime(f^{\prime\prime}(f,f)) +f^\prime(f^\prime(f^\prime(f))),</math>
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| where the tree structure is crucial.
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| ==Definition using Hopf algebra of rooted trees==
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| The [[Hopf algebra]] '''H''' of rooted trees was defined by {{harvtxt|Connes|Kreimer|1998}} in connection with [[Dirk Kreimer|Kreimer]]'s previous work on [[renormalization]] in [[quantum field theory]]. It was later discovered that the Hopf algebra was the dual of a Hopf algebra defined earlier by {{harvtxt|Grossman|Larsen|1989}} in a different context. The characters of '''H''', i.e. the homomorphisms of the underlying commutative algebra into '''R''', form a group, called the '''Butcher group'''. It corresponds to the [[formal group]] structure discovered in [[numerical analysis]] by {{harvtxt|Butcher|1972}}.
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| The '''Hopf algebra of rooted trees''' '''H''' is defined to be the [[polynomial ring]] in the variables '''t''', where '''t''' runs through rooted trees.
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| *Its [[comultiplication]] <math> \Delta:H\rightarrow H \otimes H</math> is defined by
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| :<math>\Delta(t) = t\otimes I + I \otimes t +\sum_{s\subset t} s\otimes [t\backslash s],</math>
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| where the sum is over all proper rooted subtrees '''s''' of '''t'''; <math>[t\backslash s]</math> is the monomial given by the product the variables '''t'''<sub>i</sub> formed by the rooted trees that arise on erasing all the nodes of '''s''' and connected links from '''t'''. The number of such trees is denoted by ''n''('''t'''\'''s''').
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| *Its [[counit]] is the homomorphism ε of '''H''' into '''R''' sending each variable '''t''' to zero.
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| *Its [[antipode (algebra)|antipode]] ''S'' can be defined recursively by the formula
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| :<math> S(t) = -t - \sum_{s \subset t}(-1)^{n(t\backslash s)}S([t\backslash s])s, \,\,\, S(\bullet)= -\bullet.</math>
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| The '''Butcher group''' is defined to be the set of algebra homomorphisms φ of '''H''' into '''R''' with group structure
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| :<math>\varphi_1 \star \varphi_2 (t)= (\varphi_1\otimes \varphi_2)\Delta(t).</math>
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| The inverse in the Butcher group is given by
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| :<math>\varphi^{-1}(t)=\varphi(St)</math>
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| and the identity by the counit ε.
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| ==Butcher series and Runge–Kutta method==
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| The non-linear ordinary differential equation
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| :<math> {dx(s)\over ds} = f(x(s)),\,\,\, x(0)=x_0,</math>
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| can be solved approximately by the [[Runge-Kutta method]]. This iterative scheme requires an ''m'' x ''m'' matrix
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| :<math>A=(a_{ij})</math>
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| and a vector
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| :<math>b=(b_i)</math>
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| with ''m'' components.
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| The scheme defines vectors ''x''<sub>''n''</sub> by first finding a solution ''X''<sub>1</sub>, ... , ''X''<sub>''m''</sub> of
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| :<math> X_i= x_{n-1} + h \sum_{j=1}^m a_{ij} f(X_j)</math>
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| and then setting
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| :<math>x_n=x_{n-1} +h \sum_{j=1}^m b_j f(x_j).</math>
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| {{harvtxt|Butcher|1963}} showed that the solution of the corresponding ordinary differential equations
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| :<math> X_i(s)=x_0 + s\sum_{j=1}^m a_{ij} f(X_j(s)),\,\,\, x(s)=x_0 + s \sum_{j=1}^m b_jf(X_j(s))</math>
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| has the power series expansion
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| :<math> X_i(s) = x_0 +\sum_t {s^{|t|}\over |t|!} \alpha(t) t! \sum_{j=1}^m a_{ij} \varphi_j(t)\delta_t(0),\,\,\,\,x(s) = x_0 +
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| \sum_t {s^{|t|}\over |t|!} \alpha(t) t! \varphi(t)\delta_t(0), </math>
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| where φ<sub>''j''</sub> and φ are determined recursively by
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| :<math>\varphi_j(\bullet)=1.\,\,\, \varphi_i([t_1,\cdots,t_k])=\sum_{j_1,\dots,j_k} a_{ij_1}\dots a_{ij_k} \varphi_{j_1}(t_1)\dots \varphi_{j_k}(t_k)</math>
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| and
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| :<math>\varphi(t) = \sum_{j=1}^m b_j \varphi_j(t).</math>
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| The power series above are called '''B-series''' or '''Butcher series'''.<ref name="Butcher2008" /><ref>{{citation|title=The use of Butcher series in the analysis of Newton-like iterations in Runge-Kutta formulas|journal=Applied Numerical Mathematics|volume=15 |year=1994|pages=341–356| first=K. R.|last= Jackson|first2=A. |last2=Kværnø|first3=S.P.|last3=Nørsett|doi=10.1016/0168-9274(94)00031-X|issue=3}} (Special issue to honor professor J. C. Butcher on his sixtieth birthday)</ref> The corresponding assignment φ is an element of the Butcher group. The homomorphism corresponding to the actual flow has
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| :<math> \Phi(t)={1\over t!}.</math>
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| Butcher showed that the Runge-Kutta method gives an ''n''th order approximation of the actual flow provided that φ and Φ agree on all trees with ''n'' nodes or less. Moreover {{harvtxt|Butcher|1972}} showed that the homomorphisms defined by the Runge-Kutta method form a dense subgroup of the Butcher group: in fact he showed that, given a homomorphism φ', there is a Runge-Kutta homomorphism φ agreeing with φ' to order ''n''; and that if given homomorphims φ and φ' corresponding to Runge-Kutta data (''A'', ''b'') and (''A' '', ''b' ''), the product homomorphism <math>\varphi\star \varphi^\prime</math> corresponds to the data
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| :<math> \begin{pmatrix} A & 0\\ 0 & A^\prime\\ \end{pmatrix},\,\, (b,b^\prime).</math>
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| {{harvtxt|Hairer|Wanner|1974}} proved that the Butcher group acts naturally on the functions ''f''. Indeed setting
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| :<math>\varphi\circ f= 1 +\sum_t {s^{|t|}\over |t|!} \alpha(t) t! \varphi(t)\delta_t(0),</math>
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| they proved that
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| :<math> \varphi_1\circ (\varphi_2\circ f) = (\varphi_1\star \varphi_2)\circ f.</math>
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| ==Lie algebra==
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| {{harvtxt|Connes|Kreimer|1998}} showed that associated with the Butcher group '''G''' is an infinite-dimensional Lie algebra. The existence of this Lie algebra is predicted by a theorem of {{harvtxt|Milnor|Moore|1965}}: the commutativity and natural grading on '''H''' implies that the dual '''H'''* can be identified with the [[universal enveloping algebra]] of a Lie algebra <math>\mathfrak{g}</math>. Connes and Kreimer explicitly identify <math>\mathfrak{g}</math> with a space of [[derivation (abstract algebra)|derivation]]s θ of '''H''' into '''R''', i.e. linear maps such that
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| :<math>\theta(ab)=\varepsilon(a)\theta(b) + \theta(a)\varepsilon(b),</math>
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| the formal tangent space of '''G''' at the identity ε. This forms a Lie algebra with Lie bracket
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| :<math>[\theta_1,\theta_2](t)=(\theta_1 \otimes \theta_2 -\theta_2\otimes\theta_1)\Delta(t).</math>
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| <math>\mathfrak{g}</math> is generated by the derivations θ<sub>'''t'''</sub> defined by
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| :<math>\theta_t(t^\prime)=\delta_{tt^\prime}, </math>
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| for each rooted tree '''t'''.
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| ==Renormalization==
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| {{harvtxt|Connes|Kreimer|1998}} provided a general context for using [[Hopf algebra]]ic methods to give a simple mathematical formulation of [[renormalization]] in [[quantum field theory]]. Renormalization was interpreted as [[Riemann–Hilbert problem|Birkhoff factorization]] of loops in the character group of the associated Hopf algebra. The models considered by {{harvtxt|Kreimer|1999}} had Hopf algebra '''H''' and character group '''G''', the Butcher group. {{harvtxt|Brouder|2000}} has given an account of this renormalization process in terms of Runge-Kutta data.
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| In this simplified setting, a ''renormalizable model'' has two pieces of input data:<ref>{{harvnb|Kreimer|2007}}</ref>
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| * a set of ''Feynman rules'' given by an algebra homomorphism Φ of '''H''' into the algebra ''V'' of [[Laurent series]] in ''z'' with poles of finite order;
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| * a ''renormalization scheme'' given by a linear operator ''R'' on ''V'' such that ''R'' satisfies the [[Rota-Baxter algebra|Rota-Baxter identity]]
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| ::<math>R(fg) + R(f)R(g) = R(fR(g)) + R(R(f)g)\,</math>
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| :and the image of ''R'' – ''id'' lies in the algebra ''V''<sub>+</sub> of [[power series]] in ''z''.
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| Note that ''R'' satisfies the Rota-Baxter identity if and only if ''id'' – ''R'' does. An important example is the ''[[minimal subtraction scheme]]''
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| :<math>\displaystyle R(\sum_{n} a_n z^n )= \sum_{n< 0} a_n z^n.</math>
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| In addition there is a projection ''P'' of '''H''' onto the [[augmentation ideal]] ker ε given by
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| :<math>\displaystyle P(x) = x -\varepsilon(x)1.</math>
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| To define the renormalized Feynman rules, note that the antipode ''S'' satisfies
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| :<math> m\circ (S\otimes {\rm id}) \Delta (x) =\varepsilon(x)1</math>
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| so that
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| :<math>S = - m\circ (S\otimes P)\Delta,</math>
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| The ''renormalized Feynman rules'' are given by a homomorphism <math>\Phi_S^R</math> of '''H''' into ''V'' obtained by twisting the homomorphism Φ • S. The homomorphism <math>\Phi_S^R</math> is uniquely specified by
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| :<math>\Phi_S^R = -m(S\otimes \Phi_S^R\circ P)\Delta.</math>
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| Because of the precise form of Δ, this gives a recursive formula for <math>\Phi_S^R</math>.
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| For the minimal subtraction scheme, this process can be interpreted in terms of Birkhoff factorization in the complex Butcher group. Φ can be regarded as a map γ of the unit circle into the complexification '''G'''<sub>'''C'''</sub> of '''G''' (maps into '''C''' instead of '''R'''). As such it has a Birkhoff factorization
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| :<math> \displaystyle \gamma(z)=\gamma_-(z)^{-1} \gamma_+(z),</math>
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| where γ<sub>+</sub> is [[holomorphic]] on the interior of the closed unit disk and γ<sub>–</sub> is holomorphic on its complement in the [[Riemann sphere]] '''C''' <math>\cup\{\infty\}</math> with γ<sub>–</sub>(∞) = 1. The loop γ<sub>+</sub> corresponds to the renormalized homomorphism. The evaluation at ''z'' = 0 of γ<sub>+</sub> or the renormalized homomorphism gives the ''dimensionally regularized'' values for each rooted tree.
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| In example, the Feynman rules depend on additional parameter μ, a "unit of mass". {{harvtxt|Connes|Kreimer|2001}} showed that
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| :<math>\partial_\mu \gamma_{\mu-} =0,</math>
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| so that γ<sub>μ–</sub> is independent of μ.
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| The complex Butcher group comes with a natural one-parameter group λ<sub>''w''</sub> of automorphisms, dual to that on '''H'''
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| :<math>\lambda_{w}(t)= w^{|t|}t</math>
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| for ''w'' ≠ 0 in '''C'''.
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| The loops γ<sub>μ</sub> and λ<sub>''w''</sub> · γ<sub>μ</sub> have the same negative part and, for ''t'' real,
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| :<math>\displaystyle F_t=\lim_{z=0} \gamma_-(z) \lambda_{tz}(\gamma_-(z)^{-1})</math>
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| defines a one-parameter subgroup of the complex Butcher group '''G'''<sub>'''C'''</sub> called the [[renormalization group| renormalization group flow]] (RG).
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| Its infinitesimal generator β is an element of the Lie algebra of '''G'''<sub>'''C'''</sub> and is defined by
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| :<math>\beta=\partial_t F_t|_{t=0}.</math>
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| It is called the [[beta-function]] of the model.
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| In any given model, there is usually a finite-dimensional space of complex coupling constants. The complex Butcher group acts by diffeomorphims on this space. In particular the renormalization group defines a flow on the space of coupling constants, with the beta function giving the corresponding vector field.
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| More general models in quantum field theory require rooted trees to be replaced by [[Feynman diagram]]s with vertices decorated by symbols from a finite index set. Connes and Kreimer have also defined Hopf algebras in this setting and have shown how they can be used to systematize standard computations in renormalization theory.
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| ==Example==
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| {{harvtxt|Kreimer|2007}} has given a "toy model" involving [[dimensional regularization]] for '''H''' and the algebra ''V''. If ''c'' is a positive integer and ''q''<sub>μ</sub> = ''q'' / μ is a dimensionless constant, Feynman rules can be defined recursively by
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| :<math>\displaystyle \Phi([t_1,\dots, t_n])=\int {\Phi(t_1)\cdots \Phi(t_n) \over |y|^2 + q_\mu^2} (|y|^2)^{-z({c\over 2} -1)} \, d^D y,</math>
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| where ''z'' = 1 – ''D''/2 is the regularization parameter. These integrals can be computed explicitly in terms of the [[Gamma function]] using the formula
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| :<math>\displaystyle \int {(|y|^2)^{-u}\over |y|^2 +q_\mu^2} \, d^Dy = \pi^{D/2} (q_\mu^2)^{-z-u} {\Gamma(-u +D/2)\Gamma(1+u-D/2)\over \Gamma(D/2)}.</math>
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| Taking the renormalization scheme ''R'' of minimal subtraction, the renormalized quantities <math>\Phi_S^R(t)</math> are [[polynomial]]s in <math>\log q_\mu^2</math> when evaluated at ''z'' = 0.
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| {{reflist|2}}
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| ==References==
| | Hats off to the learn brain that doing work driving the style and design, Paul Mitchell and Loreal Professionnel. Our hair care vary contains anything you need to have to make and keep a experienced glance in the convenience of your individual dwelling, from hair straighteners and hair dryers, But the real risk was just the starting just hear tocollection sky spray, a black and yellow two snakeheads a unexpected out of the drinking water that is also one particular of the black sq. |
| *{{citation|journal=Ann. Henri Poincaré|volume= 6 |year=2005|pages=343–367|title=The Hopf Algebra of Rooted Trees in Epstein-Glaser Renormalization|first=Christoph|last= Bergbauer|first2=Dirk|last2= Kreimer|authorlink2=Dirk Kreimer|arxiv=hep-th/0403207|doi=10.1007/s00023-005-0210-3|issue=2}}
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| *{{citation|last=Boutet de Monvel|first= Louis|title=Algèbre de Hopf des diagrammes de Feynman, renormalisation et factorisation de Wiener-Hopf (d'après A. Connes et D. Kreimer). [Hopf algebra of Feynman diagrams, renormalization and Wiener-Hopf factorization (following A. Connes and D. Kreimer)]|series=[[Séminaire Bourbaki]]|journal= Astérisque|volume= 290|year=2003|pages= 149–165|url=http://people.math.jussieu.fr/~boutet/renormalisation.pdf}}
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| *{{citation|title=Runge–Kutta methods and renormalization|first=Christian |last=Brouder|journal=Eur.Phys.J.|volume= C12 |year=2000|pages= 521–534|arxiv=hep-th/9904014}}
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| *{{citation|first=Christian |last=Brouder|title= Trees, Renormalization and Differential Equations|journal=BIT Numerical Mathematics|volume= 44|year= 2004|pages=425–438|url=http://www.springerlink.com/content/m334351x243t2412/|doi=10.1023/B:BITN.0000046809.66837.cc|issue=3}}
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| *{{citation|first=J.C|last=Butcher|authorlink=John C. Butcher|title=Coefficients for the study of Runge-Kutta integration processes|journal=J. Austral. Math. Soc. |volume=3 |year=1963 |pages=185–201|doi=10.1017/S1446788700027932|issue=2}}
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| *{{citation|first=J.C|last=Butcher|authorlink=John C. Butcher|title=An algebraic theory of integration methods|journal=Math. Comput.|volume=26|issue=117|year=1972|pages=79–106|jstor=2004720|doi=10.2307/2004720}}
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| *{{Citation | last1=Butcher | first1=John C. | author1-link=John C. Butcher | title=Numerical methods for ordinary differential equations | publisher=John Wiley & Sons Ltd. | edition=2nd | isbn=978-0-470-72335-7 | mr=2401398 | year=2008}}
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| *{{citation|first=J.C|last=Butcher|authorlink=John C. Butcher|title=Trees and numerical methods for ordinary differential equations|url=http://www.springerlink.com/content/un0168l544n80250/|journal=Numerical Algorithms|publisher=Springer online|year=2009}}
| |
| *{{citation|first=Arthur|last=Cayley|authorlink=Arthur Cayley|title=On the theory of analytic forms called trees|url= http://www.archive.org/stream/collectedmathema03cayluoft#page/242/mode/1up|journal=[[Philosophical Magazine]]|volume=XIII|year=1857|pages=172–176}} (also in Volume 3 of the Collected Works of Cayley, pages 242–246)
| |
| *{{citation|first=Alain|last=Connes|authorlink=Alain Connes|first2=Dirk|last2=Kreimer|authorlink2=Dirk Kreimer|title=Hopf Algebras, Renormalization and Noncommutative Geometry|journal=Communications in Mathematical Physics|volume= 199|year= 1998|pages=203–242|url=http://www.alainconnes.org/docs/ncgk.pdf|doi=10.1007/s002200050499}}
| |
| *{{citation|first=Alain|last=Connes|authorlink=Alain Connes|first2=Dirk|last2=Kreimer|authorlink2=Dirk Kreimer|title=Lessons from quantum field theory: Hopf algebras and spacetime geometries|journal=[[Letters in Mathematical Physics]]|volume= 48 |year=1999|pages= 85–96|doi=10.1023/A:1007523409317}}
| |
| *{{citation|first=Alain|last=Connes|authorlink=Alain Connes|first2=Dirk|last2=Kreimer|authorlink2=Dirk Kreimer|title=Renormalization in quantum field theory and the Riemann-Hilbert problem. I. The Hopf algebra structure of graphs and the main theorem|journal=Comm. Math. Phys.|volume= 210|year=2000|pages=249–273
| |
| |url=http://www.alainconnes.org/docs/RH1.pdf|doi=10.1007/s002200050779}}
| |
| *{{citation|first=Alain|last=Connes|authorlink=Alain Connes|first2=Dirk|last2=Kreimer|authorlink2=Dirk Kreimer|title= Renormalization in quantum field theory and the Riemann-Hilbert problem. II. The β-function, diffeomorphisms and the renormalization group|journal= Comm. In Math. Phys.|volume= 216|pages= 215–241|year=2001|
| |
| url=http://www.alainconnes.org/docs/RH2.pdf|doi=10.1007/PL00005547}}
| |
| *{{citation|title=Elements of noncommutative geometry|first=José |last=Gracia-Bondía|first2= Joseph C.|last2= Várilly|first3= Héctor|last3= Figueroa|publisher=Birkhäuser|year=2000|isbn=0-8176-4124-6}}, Chapter 14.
| |
| *{{citation|first=R.|last= Grossman|first2= R.|last2= Larson|title= Hopf algebraic structures of families of trees|journal= Journal Algebra|volume=26|year= 1989| pages= 184–210|url=http://users.lac.uic.edu/~grossman/papers/journal-03.pdf}}
| |
| *{{citation|title=On the Butcher group and general multi-value methods|journal=Computing|volume= 13|year= 1974|pages=1–15|first=E. |last=Hairer|first2=G.|last2= Wanner|url=http://www.springerlink.com/content/e6r7327737lq3516/|doi=10.1007/BF02268387}}
| |
| *{{citation|last=Kreimer|first= Dirk|authorlink=Dirk Kreimer|title=On the Hopf algebra structure of perturbative quantum field theories|journal=Adv. Theor. Math. Phys.|volume=2|year=1998|pages= 303–334|arxiv=q-alg/9707029}}
| |
| *{{citation|arxiv=hep-th/9901099|last=Kreimer|first= Dirk|authorlink=Dirk Kreimer|title=Chen's iterated integral represents the operator product expansion|journal=Adv. Theor. Math. Phys.|volume= 3 |year=1999|pages=627–670}}
| |
| *{{citation|last=Kreimer|first= Dirk|authorlink=Dirk Kreimer|title= Factorization in Quantum Field Theory: An Exercise in Hopf Algebras and Local Singularities|
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| series=Frontiers in Number Theory, Physics, and Geometry II|publisher=Springer|year=2007|pages=715–736|arxiv=hep-th/0306020}}
| |
| *{{Citation | last1=Milnor | first1=John Willard | author1-link=John Milnor | last2=Moore | first2=John C. | title=On the structure of Hopf algebras | jstor=1970615 | mr=0174052 | year=1965 | journal=[[Annals of Mathematics]] | series = Second Series | volume=81 | issue=2 | pages=211–264 | doi=10.2307/1970615}}
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| [[Category:Combinatorics]] | | for the earn, a suction mouth is on the shore facet wins nevertheless not touch the floor, A lot of have commented positively on the simple fact that [http://tinyurl.com/mdm2hs2 ghd straightener] it is a unique edition and that it life up to it with the situation getting likened to a clutch bag, so can be used for other issues other than just carrying your straighteners in. |
| [[Category:Numerical analysis]]
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| [[Category:Quantum field theory]]
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| [[Category:Renormalization group]]
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| [[Category:Hopf algebras]]
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