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seen Apr 3 '13 at 19:13

Dec
11
comment How do mathematicians think about the existence of numbers?
@CBenni Thanks!
Dec
9
comment left regular representation of $G$ with respect to $g$
Ok, thank you !
Dec
9
comment left regular representation of $G$ with respect to $g$
Thank you for the answer. I want to prove that $\lambda_g$ is surjective and injective directly (I know the definitions), but how?
Dec
2
comment An abelian group is not isomorphic to an non-abelian group.
Yes, an isomorphism is a bijective homomorphism.
Dec
2
comment Show that $\Bbb{Z}/4\Bbb{Z}\times\Bbb{Z}/2\Bbb{Z}\not\cong\Bbb{Z}/8\Bbb{Z}$
@Mj125 Thanks for the quick reply.
Nov
27
comment A noneempty subset $H$ of a finite goup $G$ is a subgroup if and only if $H$ is closed
Thank you, I get it now. This is much better.
Nov
18
comment Group(Non-abelian) Multiplication Table
@BrianM.Scott I came up with this: $$\begin{array}{ l | c r r r r r } * & e & a & b & c & d &f \\ \hline e & e & a & b & c & d & f \\ a & a & b & e & d&f&c \\ b&b&e&a&f&c&d\\ c&c&f&d&e&b&a\\ d&d&c&f&a&e&b\\ f&f&d&c&b&a&e\\ \end{array}$$ is this correct?
Oct
23
comment How can I Prove that $[(p \to\neg q) \wedge q] \to \neg p$ is a tautology?
@PeterSmith See Edit
Oct
22
comment Prove that the function $\Phi :\mathcal{F}(X,Y)\longrightarrow Y$, is not injective.
Great, I get it now! Thank you
Oct
9
comment Proving $\sum_{i=1}^{n}{\frac{i}{2^i}}=2-\frac{n+2}{2^n}$ by induction.
That was quick! Thank you.