Automorphism: Difference between revisions

From formulasearchengine
Jump to navigation Jump to search
en>MathKnight-at-TAU
 
en>Monkbot
Line 1: Line 1:
"Why does my computer keep freezing up?" I was asked by a great deal of individuals the cause of their pc freeze difficulties. And I am fed up with spending much time inside answering the question time plus time again. This post is to tell we the real cause of the PC Freezes.<br><br>Google Chrome crashes on Windows 7 by the corrupted cache contents plus problems with all the stored browsing data. Delete the browsing information plus well-defined the contents of the cache to solve this issue.<br><br>With RegCure to boost the start up and shut down of the computer. The program shows the scan progress plus you shouldn't worry where it is very working at which time. It shows we what happens. Dynamic link library section of the registry will cause serious application failures. RegCure restores plus repairs the registry and keeps you out of DLL. RegCure is able to make individual corrections, thus it can functions for your needs.<br><br>Registry cleaners have been crafted for one purpose - to wash out the 'registry'. This really is the central database which Windows relies on to function. Without this database, Windows wouldn't even exist. It's so significant, that your computer is continually adding plus updating the files inside it, even when you're browsing the Internet (like now). This really is good, however, the problems occur when a few of those files become corrupt or lost. This happens a lot, plus it takes a advantageous tool to fix it.<br><br>So to fix this, we really have to be capable to create all registry files non-corrupted again. This can dramatically speed up the loading time of your computer and may allow we to do a big amount of aspects on it again. And fixing these files couldn't be easier - we merely should use a tool called a [http://bestregistrycleanerfix.com/regzooka zookaware].<br><br>We should additionally see with it it is very easy to download and install. You should avoid those products that may need you a especially complicated set of instructions. Furthermore, you should no longer need any other program requirements.<br><br>Most probably in the event you are experiencing a slow computer it will be a couple years older. We furthermore might not have been told that while you use a computer everyday; there are certain details which it needs to continue running in its ideal performance. We additionally could not even own any diagnostic tools that may receive a PC running like brand-new again. So do not allow which stop we from getting your program cleaned. With access to the web you will find the tools which will help we receive a system running like brand-new again.<br><br>Before you buy a complete unique system; it is very time to receive the aged one cleaned up to begin getting more performed online today! Visit our site under and access the most reputable registry cleaner software available.
In [[mathematics]], an '''automorphism''' is an [[isomorphism]] from a [[mathematical object]] to itself. It is, in some sense, a [[symmetry]] of the object, and a way of [[map (mathematics)|mapping]] the object to itself while preserving all of its structure. The set of all automorphisms of an object forms a [[group (mathematics)|group]], called the '''automorphism group'''. It is, loosely speaking, the [[symmetry group]] of the object.
 
==Definition==
The exact definition of an automorphism depends on the type of "mathematical object" in question and what, precisely, constitutes an "isomorphism" of that object. The most general setting in which these words have meaning is an abstract branch of mathematics called [[category theory]]. Category theory deals with abstract objects and [[morphism]]s between those objects.
 
In category theory, an automorphism is an [[endomorphism]] (i.e. a [[morphism]] from an object to itself) which is also an [[isomorphism]] (in the categorical sense of the word).
 
This is a very abstract definition since, in category theory, morphisms aren't necessarily functions and objects aren't necessarily sets. In most concrete settings, however, the objects will be sets with some additional structure and the morphisms will be functions preserving that structure.
 
In the context of [[abstract algebra]], for example, a mathematical object is an [[algebraic structure]] such as a [[group (mathematics)|group]], [[ring (mathematics)|ring]], or [[vector space]]. An isomorphism is simply a [[bijective]] [[homomorphism]]. (The definition of a homomorphism depends on the type of algebraic structure; see, for example: [[group homomorphism]], [[ring homomorphism]], and [[linear operator]]).
 
The [[identity morphism]] ([[identity mapping]]) is called the '''trivial automorphism''' in some contexts. Respectively, other (non-identity) automorphisms are called '''nontrivial automorphisms'''.
 
==Automorphism group==
If the automorphisms of an object ''X'' form a set (instead of a proper [[class (set theory)|class]]), then they form a [[group (mathematics)|group]] under [[Function composition|composition]] of [[morphism]]s. This group is called the '''automorphism group''' of ''X''. That this is indeed a group is simple to see:
* [[Closure (binary operation)|Closure]]: composition of two endomorphisms is another endomorphism.
* [[Associativity]]: composition of morphisms is ''always'' associative.
* [[Identity element|Identity]]: the identity is the identity morphism from an object to itself which exists by definition.
* [[Inverse element|Inverses]]: by definition every isomorphism has an inverse which is also an isomorphism, and since the inverse is also an endomorphism of the same object it is an automorphism.
 
The automorphism group of an object ''X'' in a category ''C'' is denoted Aut<sub>''C''</sub>(''X''), or simply Aut(''X'') if the category is clear from context.
 
==Examples==
* In [[set theory]], an arbitrary [[permutation]] of the elements of a set ''X'' is an automorphism. The automorphism group of ''X'' is also called the [[symmetric group]] on ''X''.
* In [[elementary arithmetic]], the set of [[integer]]s, '''Z''', considered as a group under addition, has a unique nontrivial automorphism: negation. Considered as a [[ring (mathematics)|ring]], however, it has only the trivial automorphism. Generally speaking, negation is an automorphism of any [[abelian group]], but not of a ring or field.
* A group automorphism is a [[group isomorphism]] from a group to itself. Informally, it is a permutation of the group elements such that the structure remains unchanged. For every group ''G'' there is a natural group homomorphism ''G'' → Aut(''G'') whose [[image (mathematics)|image]] is the group Inn(''G'') of [[inner automorphism]]s and whose [[kernel (algebra)|kernel]] is the [[center (group theory)|center]] of ''G''. Thus, if ''G'' has [[Trivial group|trivial]] center it can be embedded into its own automorphism group.<ref name=Pahl>
 
{{cite book |url=http://books.google.com/?id=kvoaoWOfqd8C&pg=PA376 |page=376 |chapter=§7.5.5 Automorphisms |title=Mathematical foundations of computational engineering |edition=Felix Pahl translation |author=PJ Pahl, R Damrath |isbn=3-540-67995-2 |year=2001 |publisher=Springer}}
 
</ref>
* In [[linear algebra]], an endomorphism of a [[vector space]] ''V'' is a [[linear transformation|linear operator]] ''V'' → ''V''. An automorphism is an invertible linear operator on ''V''. When the vector space is finite-dimensional, the automorphism group of ''V'' is the same as the [[general linear group]], GL(''V'').
* A field automorphism is a [[bijection|bijective]] [[ring homomorphism]] from a [[field (mathematics)|field]] to itself. In the cases of the [[rational number]]s ('''Q''') and the [[real number]]s ('''R''') there are no nontrivial field automorphisms. Some subfields of '''R''' have nontrivial field automorphisms, which however do not extend to all of '''R''' (because they cannot preserve the property of a number having a square root in '''R'''). In the case of the [[complex number]]s, '''C''', there is a unique nontrivial automorphism that sends '''R''' into '''R''': [[complex conjugate|complex conjugation]], but there are infinitely ([[uncountable|uncountably]]) many "wild" automorphisms (assuming the [[axiom of choice]]).<ref>{{cite journal | last = Yale | first = Paul B. | journal = Mathematics Magazine | title = Automorphisms of the Complex Numbers | volume = 39 | issue = 3 |date=May 1966 | pages = 135–141 | url = http://www.maa.org/sites/default/files/pdf/upload_library/22/Ford/PaulBYale.pdf | doi = 10.2307/2689301 | jstor = 2689301}}</ref> Field automorphisms are important to the theory of [[field extension]]s, in particular [[Galois extension]]s. In the case of a Galois extension ''L''/''K'' the [[subgroup]] of all automorphisms of ''L'' fixing ''K'' pointwise is called the [[Galois group]] of the extension.
* In [[graph theory]] an [[graph automorphism|automorphism of a graph]] is a permutation of the nodes that preserves edges and non-edges. In particular, if two nodes are joined by an edge, so are their images under the permutation.
* For relations, see [[Isomorphism#A relation-preserving isomorphism|relation-preserving automorphism]].
** In [[order theory]], see [[order automorphism]].
* In [[geometry]], an automorphism may be called a [[motion (geometry)|motion]] of the space. Specialized terminology is also used:
** In [[metric geometry]] an automorphism is a self-[[isometry]]. The automorphism group is also called the [[isometry group]].
** In the category of [[Riemann surface]]s, an automorphism is a bijective [[biholomorphy|biholomorphic]] map (also called a [[conformal map]]), from a surface to itself. For example, the automorphisms of the [[Riemann sphere]] are [[Möbius transformation]]s.
** An automorphism of a differentiable [[manifold]] ''M'' is a [[diffeomorphism]] from ''M'' to itself. The automorphism group is sometimes denoted Diff(''M'').
** In [[topology]], morphisms between topological spaces are called [[Continuous function (topology)|continuous maps]], and an automorphism of a topological space is a [[homeomorphism]] of the space to itself, or self-homeomorphism (see [[homeomorphism group]]). In this example it is ''not sufficient'' for a morphism to be bijective to be an isomorphism.
 
==History==
One of the earliest group automorphisms (automorphism of a group, not simply a group of automorphisms of points) was given by the Irish mathematician [[William Rowan Hamilton]] in 1856, in his [[icosian calculus]], where he discovered an order two automorphism,<ref>{{Cite journal
|title=Memorandum respecting a new System of Roots of Unity
|author=Sir William Rowan Hamilton
|author-link=William Rowan Hamilton
|url=http://www.maths.tcd.ie/pub/HistMath/People/Hamilton/Icosian/NewSys.pdf
|journal=[[Philosophical Magazine]]
|volume=12
|year=1856
|pages=446
}}</ref> writing:
{{quotation|so that <math>\mu</math> is a new fifth root of unity, connected with the former fifth root <math>\lambda</math> by relations of perfect reciprocity.}}
 
==Inner and outer automorphisms==
In some categories—notably [[group (mathematics)|groups]], [[ring (mathematics)|rings]], and [[Lie algebra]]s—it is possible to separate automorphisms into two types, called "inner" and "outer" automorphisms.
 
In the case of groups, the [[inner automorphism]]s are the conjugations by the elements of the group itself. For each element ''a'' of a group ''G'', conjugation by ''a'' is the operation φ<sub>''a''</sub> : ''G''&nbsp;→&nbsp;''G'' given by <math> \varphi_a (g) = a g a^{-1} </math> (or ''a''<sup>−1</sup>''ga''; usage varies). One can easily check that conjugation by ''a'' is a group automorphism. The inner automorphisms form a [[normal subgroup]] of Aut(''G''), denoted by Inn(''G''); this is called [[Goursat's lemma]].
 
The other automorphisms are called [[outer automorphism]]s. The [[quotient group]] Aut(''G'')&nbsp;/&nbsp;Inn(''G'') is usually denoted by Out(''G''); the non-trivial elements are the cosets that contain the outer automorphisms.
 
The same definition holds in any [[unital algebra|unital]] [[ring (mathematics)|ring]] or [[algebra over a field|algebra]] where ''a'' is any [[Unit (ring theory)|invertible element]]. For [[Lie algebra]]s the definition is slightly different.
 
==See also==
* [[endomorphism ring]]
* [[antiautomorphism]]
* [[Frobenius automorphism]]
* [[morphism]]
* [[characteristic subgroup]]
 
==References==
<!-- See [[Wikipedia:Footnotes]] for instructions. -->
<references />
 
==External links==
* [http://www.encyclopediaofmath.org/index.php/Automorphism ''Automorphism'' at Encyclopaedia of Mathematics]
* {{MathWorld | urlname=Automorphism | title = Automorphism}}
 
[[Category:Morphisms]]
[[Category:Abstract algebra]]
[[Category:Symmetry]]

Revision as of 22:12, 14 January 2014

In mathematics, an automorphism is an isomorphism from a mathematical object to itself. It is, in some sense, a symmetry of the object, and a way of mapping the object to itself while preserving all of its structure. The set of all automorphisms of an object forms a group, called the automorphism group. It is, loosely speaking, the symmetry group of the object.

Definition

The exact definition of an automorphism depends on the type of "mathematical object" in question and what, precisely, constitutes an "isomorphism" of that object. The most general setting in which these words have meaning is an abstract branch of mathematics called category theory. Category theory deals with abstract objects and morphisms between those objects.

In category theory, an automorphism is an endomorphism (i.e. a morphism from an object to itself) which is also an isomorphism (in the categorical sense of the word).

This is a very abstract definition since, in category theory, morphisms aren't necessarily functions and objects aren't necessarily sets. In most concrete settings, however, the objects will be sets with some additional structure and the morphisms will be functions preserving that structure.

In the context of abstract algebra, for example, a mathematical object is an algebraic structure such as a group, ring, or vector space. An isomorphism is simply a bijective homomorphism. (The definition of a homomorphism depends on the type of algebraic structure; see, for example: group homomorphism, ring homomorphism, and linear operator).

The identity morphism (identity mapping) is called the trivial automorphism in some contexts. Respectively, other (non-identity) automorphisms are called nontrivial automorphisms.

Automorphism group

If the automorphisms of an object X form a set (instead of a proper class), then they form a group under composition of morphisms. This group is called the automorphism group of X. That this is indeed a group is simple to see:

  • Closure: composition of two endomorphisms is another endomorphism.
  • Associativity: composition of morphisms is always associative.
  • Identity: the identity is the identity morphism from an object to itself which exists by definition.
  • Inverses: by definition every isomorphism has an inverse which is also an isomorphism, and since the inverse is also an endomorphism of the same object it is an automorphism.

The automorphism group of an object X in a category C is denoted AutC(X), or simply Aut(X) if the category is clear from context.

Examples

History

One of the earliest group automorphisms (automorphism of a group, not simply a group of automorphisms of points) was given by the Irish mathematician William Rowan Hamilton in 1856, in his icosian calculus, where he discovered an order two automorphism,[3] writing: 36 year-old Diving Instructor (Open water ) Vancamp from Kuujjuaq, spends time with pursuits for instance gardening, public listed property developers in singapore developers in singapore and cigar smoking. Of late took some time to go China Danxia.

Inner and outer automorphisms

In some categories—notably groups, rings, and Lie algebras—it is possible to separate automorphisms into two types, called "inner" and "outer" automorphisms.

In the case of groups, the inner automorphisms are the conjugations by the elements of the group itself. For each element a of a group G, conjugation by a is the operation φa : G → G given by φa(g)=aga1 (or a−1ga; usage varies). One can easily check that conjugation by a is a group automorphism. The inner automorphisms form a normal subgroup of Aut(G), denoted by Inn(G); this is called Goursat's lemma.

The other automorphisms are called outer automorphisms. The quotient group Aut(G) / Inn(G) is usually denoted by Out(G); the non-trivial elements are the cosets that contain the outer automorphisms.

The same definition holds in any unital ring or algebra where a is any invertible element. For Lie algebras the definition is slightly different.

See also

References

  1. 20 year-old Real Estate Agent Rusty from Saint-Paul, has hobbies and interests which includes monopoly, property developers in singapore and poker. Will soon undertake a contiki trip that may include going to the Lower Valley of the Omo.

    My blog: http://www.primaboinca.com/view_profile.php?userid=5889534
  2. One of the biggest reasons investing in a Singapore new launch is an effective things is as a result of it is doable to be lent massive quantities of money at very low interest rates that you should utilize to purchase it. Then, if property values continue to go up, then you'll get a really high return on funding (ROI). Simply make sure you purchase one of the higher properties, reminiscent of the ones at Fernvale the Riverbank or any Singapore landed property Get Earnings by means of Renting

    In its statement, the singapore property listing - website link, government claimed that the majority citizens buying their first residence won't be hurt by the new measures. Some concessions can even be prolonged to chose teams of consumers, similar to married couples with a minimum of one Singaporean partner who are purchasing their second property so long as they intend to promote their first residential property. Lower the LTV limit on housing loans granted by monetary establishments regulated by MAS from 70% to 60% for property purchasers who are individuals with a number of outstanding housing loans on the time of the brand new housing purchase. Singapore Property Measures - 30 August 2010 The most popular seek for the number of bedrooms in Singapore is 4, followed by 2 and three. Lush Acres EC @ Sengkang

    Discover out more about real estate funding in the area, together with info on international funding incentives and property possession. Many Singaporeans have been investing in property across the causeway in recent years, attracted by comparatively low prices. However, those who need to exit their investments quickly are likely to face significant challenges when trying to sell their property – and could finally be stuck with a property they can't sell. Career improvement programmes, in-house valuation, auctions and administrative help, venture advertising and marketing, skilled talks and traisning are continuously planned for the sales associates to help them obtain better outcomes for his or her shoppers while at Knight Frank Singapore. No change Present Rules

    Extending the tax exemption would help. The exemption, which may be as a lot as $2 million per family, covers individuals who negotiate a principal reduction on their existing mortgage, sell their house short (i.e., for lower than the excellent loans), or take part in a foreclosure course of. An extension of theexemption would seem like a common-sense means to assist stabilize the housing market, but the political turmoil around the fiscal-cliff negotiations means widespread sense could not win out. Home Minority Chief Nancy Pelosi (D-Calif.) believes that the mortgage relief provision will be on the table during the grand-cut price talks, in response to communications director Nadeam Elshami. Buying or promoting of blue mild bulbs is unlawful.

    A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running

    The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more

    There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang
  3. One of the biggest reasons investing in a Singapore new launch is an effective things is as a result of it is doable to be lent massive quantities of money at very low interest rates that you should utilize to purchase it. Then, if property values continue to go up, then you'll get a really high return on funding (ROI). Simply make sure you purchase one of the higher properties, reminiscent of the ones at Fernvale the Riverbank or any Singapore landed property Get Earnings by means of Renting

    In its statement, the singapore property listing - website link, government claimed that the majority citizens buying their first residence won't be hurt by the new measures. Some concessions can even be prolonged to chose teams of consumers, similar to married couples with a minimum of one Singaporean partner who are purchasing their second property so long as they intend to promote their first residential property. Lower the LTV limit on housing loans granted by monetary establishments regulated by MAS from 70% to 60% for property purchasers who are individuals with a number of outstanding housing loans on the time of the brand new housing purchase. Singapore Property Measures - 30 August 2010 The most popular seek for the number of bedrooms in Singapore is 4, followed by 2 and three. Lush Acres EC @ Sengkang

    Discover out more about real estate funding in the area, together with info on international funding incentives and property possession. Many Singaporeans have been investing in property across the causeway in recent years, attracted by comparatively low prices. However, those who need to exit their investments quickly are likely to face significant challenges when trying to sell their property – and could finally be stuck with a property they can't sell. Career improvement programmes, in-house valuation, auctions and administrative help, venture advertising and marketing, skilled talks and traisning are continuously planned for the sales associates to help them obtain better outcomes for his or her shoppers while at Knight Frank Singapore. No change Present Rules

    Extending the tax exemption would help. The exemption, which may be as a lot as $2 million per family, covers individuals who negotiate a principal reduction on their existing mortgage, sell their house short (i.e., for lower than the excellent loans), or take part in a foreclosure course of. An extension of theexemption would seem like a common-sense means to assist stabilize the housing market, but the political turmoil around the fiscal-cliff negotiations means widespread sense could not win out. Home Minority Chief Nancy Pelosi (D-Calif.) believes that the mortgage relief provision will be on the table during the grand-cut price talks, in response to communications director Nadeam Elshami. Buying or promoting of blue mild bulbs is unlawful.

    A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running

    The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more

    There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang

External links

  • Automorphism at Encyclopaedia of Mathematics


  • I had like 17 domains hosted on single account, and never had any special troubles. If you are not happy with the service you will get your money back with in 45 days, that's guaranteed. But the Search Engine utility inside the Hostgator account furnished an instant score for my launched website. Fantastico is unable to install WordPress in a directory which already have any file i.e to install WordPress using Fantastico the destination directory must be empty and it should not have any previous installation files. When you share great information, others will take note. Once your hosting is purchased, you will need to setup your domain name to point to your hosting. Money Back: All accounts of Hostgator come with a 45 day money back guarantee. If you have any queries relating to where by and how to use Hostgator Discount Coupon, you can make contact with us at our site. If you are starting up a website or don't have too much website traffic coming your way, a shared plan is more than enough. Condition you want to take advantage of the worldwide web you prerequisite a HostGator web page, -1 of the most trusted and unfailing web suppliers on the world wide web today. Since, single server is shared by 700 to 800 websites, you cannot expect much speed.



    Hostgator tutorials on how to install Wordpress need not be complicated, especially when you will be dealing with a web hosting service that is friendly for novice webmasters and a blogging platform that is as intuitive as riding a bike. After that you can get Hostgator to host your domain and use the wordpress to do the blogging. Once you start site flipping, trust me you will not be able to stop. I cut my webmaster teeth on Control Panel many years ago, but since had left for other hosting companies with more commercial (cough, cough) interfaces. If you don't like it, you can chalk it up to experience and go on. First, find a good starter template design. When I signed up, I did a search for current "HostGator codes" on the web, which enabled me to receive a one-word entry for a discount. Your posts, comments, and pictures will all be imported into your new WordPress blog.