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 Yearling
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Feb
2
comment $K(G,1)$ for a torsion-free group $G$
@MikeMiller Wall's finiteness obstruction can only be used if you can somehow first show that your complex is finitely dominated, though.
Nov
13
revised Smallest 3-category not equivalent to a strict 3-category
added 84 characters in body
Nov
13
answered Smallest 3-category not equivalent to a strict 3-category
Nov
13
comment groupoids and localization in categories
Since you are learning homology, the category of chain complexes of abelian groups should be interesting to you. A counter-example to the hypothesis that the localization a category is a groupoid is that there are induced maps on homology which are not isomorphisms.
Nov
1
answered If $G$ is a group such that any two commutators commute, $G$ is solvable
Oct
28
comment Show $A_n$ has no subgroups of index 2
@Aniket If you read my post, you will see that this is not a question, but a hint for the OP.
Oct
28
answered Show $A_n$ has no subgroups of index 2
Oct
28
reviewed Approve Modified Z-transform
Oct
27
reviewed Approve outer measure and Sigma algebra of $\mu$-measurable sets
Oct
27
reviewed Approve Trig identity $\frac{\cos x}{\sec x} + \frac{\sin x}{\csc x} = \csc^2x - \cot^2x$
Oct
27
reviewed Approve Bracket expansion, keeps failing tests.
Oct
26
comment Is it true that $(R\times S)[G]\cong R[G]\times S[G]$?
@seeker Do you mean the zero ring? If so, then yes, since $0[G]=0$.
Oct
26
comment Is it true that $(R\times S)[G]\cong R[G]\times S[G]$?
Did you try to write down some maps between them?
Oct
26
comment The rationals as an additive group is free?
@Jim This is implicit in the whole discussion.
Oct
26
answered The rationals as an additive group is free?
Oct
25
reviewed Approve Re-arrangement of a series
Oct
24
awarded  Yearling
Oct
23
reviewed Reject How to find the equation of the graph reflected about a line?
Oct
23
reviewed Approve $T^n=1$ then the vector space has $T-$eigenvectors.
Oct
23
answered universal property in quotient topology