翻訳と辞書
Words near each other
・ "O" Is for Outlaw
・ "O"-Jung.Ban.Hap.
・ "Ode-to-Napoleon" hexachord
・ "Oh Yeah!" Live
・ "Our Contemporary" regional art exhibition (Leningrad, 1975)
・ "P" Is for Peril
・ "Pimpernel" Smith
・ "Polish death camp" controversy
・ "Pro knigi" ("About books")
・ "Prosopa" Greek Television Awards
・ "Pussy Cats" Starring the Walkmen
・ "Q" Is for Quarry
・ "R" Is for Ricochet
・ "R" The King (2016 film)
・ "Rags" Ragland
・ ! (album)
・ ! (disambiguation)
・ !!
・ !!!
・ !!! (album)
・ !!Destroy-Oh-Boy!!
・ !Action Pact!
・ !Arriba! La Pachanga
・ !Hero
・ !Hero (album)
・ !Kung language
・ !Oka Tokat
・ !PAUS3
・ !T.O.O.H.!
・ !Women Art Revolution


Dictionary Lists
翻訳と辞書 辞書検索 [ 開発暫定版 ]
スポンサード リンク

quotient category : ウィキペディア英語版
quotient category
In mathematics, a quotient category is a category obtained from another one by identifying sets of morphisms. The notion is similar to that of a quotient group or quotient space, but in the categorical setting.
==Definition==

Let ''C'' be a category. A ''congruence relation'' ''R'' on ''C'' is given by: for each pair of objects ''X'', ''Y'' in ''C'', an equivalence relation ''R''''X'',''Y'' on Hom(''X'',''Y''), such that the equivalence relations respect composition of morphisms. That is, if
:f_1,f_2 : X \to Y\,
are related in Hom(''X'', ''Y'') and
:g_1,g_2 : Y \to Z\,
are related in Hom(''Y'', ''Z'') then ''g''1''f''1, ''g''1''f''2, ''g''2''f''1 and ''g''2''f''2 are related in Hom(''X'', ''Z'').
Given a congruence relation ''R'' on ''C'' we can define the quotient category ''C''/''R'' as the category whose objects are those of ''C'' and whose morphisms are equivalence classes of morphisms in ''C''. That is,
:\mathrm_}(X,Y) = \mathrm_.
Composition of morphisms in ''C''/''R'' is well-defined since ''R'' is a congruence relation.
There is also a notion of taking the quotient of an Abelian category ''A'' by a Serre subcategory ''B''. This is done as follows. The objects of ''A/B'' are the objects of ''A''. Given two objects ''X'' and ''Y'' of ''A'', we define the set of morphisms from ''X'' to ''Y'' in ''A/B'' to be \varinjlim \mathrm_A(X', Y/Y') where the limit is over subobjects X' \subseteq X and Y' \subseteq Y such that X/X', Y' \in B. Then ''A/B'' is an Abelian category, and there is a canonical functor Q \colon A \to A/B. This Abelian quotient satisfies the universal property that if ''C'' is any other Abelian category, and F \colon A \to C is an exact functor such that ''F(b)'' is a zero object of ''C'' for each b \in B, then there is a unique exact functor \overline \colon A/B \to C such that F = \overline \circ Q. (See ().)

抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)
ウィキペディアで「quotient category」の詳細全文を読む



スポンサード リンク
翻訳と辞書 : 翻訳のためのインターネットリソース

Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.