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Ext functor

In mathematics, the Ext functors are the derived functors of the Hom functor. Along with the Tor functor, Ext is one of the core concepts of homological algebra, in which ideas from algebraic topology are used to define invariants of algebraic structures. The cohomology of groups, Lie algebras, and associative algebras can all be defined in terms of Ext.…

Products, Properties of Ext & Important special cases

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Overview

Definition

Properties of Ext

Ext and extensions

Construction of Ext in abelian categories

The derived category and the Yoneda product

Important special cases

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Map overview Semantic statistics

Ext functor

Nodes100
Edges99
Triples0
Avg. degree1.98
Density0.02
Components1

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Important terminology

displaystyle ext operatorname category groups extensions ring algebra commutative cohomology defined abelian derived group baer hom projective map one equivalence

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