User talk:Jallotta/Yoneda Extensions

Put in the categories: Category:Homological algebra, Category:Binary operations (and more) Jallotta (talk) 22:09, 14 February 2010 (UTC)

Definition of Baer sum
In the definition of Baer sum under Ext in abelian categories [Weibel, p. 79] has, instead of $$X_n$$, the object $$Y_n$$ defined to be the quotient of $$X_n$$ by the skew diagonal copy of $$B$$. —Preceding unsigned comment added by Holmerr (talk • contribs) 18:46, 13 July 2010 (UTC)