Babak S.

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Counting is a less precise tool for infinite sets than for finite ones. The shepherdess who can count her flock of a hundred sheep will know if the wolf has taken one; but, if she has an infinite flock, she won't notice until almost all of her sheep have been lost.

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Peter J. Cameron

All I am doing here as hints or answers, are dedicated to him.

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286 Favorites

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Generators and Relations for A_4

group-theory

oct 19 '10 at 4:37 HJRW 1,028

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348

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How do I show that every group of order 90 is not simple?

group-theory

may 18 '12 at 18:03 Zev Chonoles 57.5k

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157

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Is this inequality true?

homework inequality

jun 1 '12 at 18:12 leonbloy 13.1k

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Is there anything like GF(6)?

finite-fields

jul 26 '11 at 20:36 Mark Bennet 11.1k

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Proving $\mathbb{Z}[i] / (7+5i) \cong \mathbb{Z}_{74}$.

abstract-algebra

nov 6 at 0:48 Community♦ 1

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Groups where all elements are order 3

abstract-algebra group-theory

jun 10 '12 at 1:51 Arturo Magidin 159k

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Quotient of two free abelian groups of the same rank is finite?

group-theory abelian-groups free-groups

jun 11 '12 at 16:29 Steve D 5,305

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Action of group on direct product, quotient group

group-theory

jun 5 '12 at 0:34 Geoff Robinson 10.1k

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104

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Group of arbitrary order

finite-groups

jun 22 '12 at 6:19 Gerry Myerson 87k

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All subgroup are Normal

group-theory

jun 28 '12 at 10:14 Tobias Kildetoft 4,991

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Find all non-abelian groups of order 105.

group-theory finite-groups

may 31 '12 at 0:04 DonAntonio 50.7k

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Matrix with no eigenvalues

linear-algebra

jun 14 '12 at 8:19 Jyrki Lahtonen 31.9k

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On groups of order $6n$.

group-theory

jan 14 at 19:21 Chris Eagle 21k

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Show $\mathrm{gcd}(7a+5,4a+3)=1$.

number-theory

feb 8 at 4:44 Community♦ 1

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Some questions on the Frattini subgroup

group-theory finite-groups

oct 8 '11 at 18:29 Ted 7,854

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Show that if $x\in N$, then $\left \vert x^{N} \right \vert$ divides $\left \vert x^{G} \right \vert$

homework group-theory

dec 30 at 4:11 Alexander Gruber♦ 15.7k

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If there exists a subgroup contained in all nontrivial subgroups of $G$, then $G$ is quasicyclic.

abstract-algebra group-theory abelian-groups p-groups

dec 6 at 17:59 Hagen von Eitzen 47.3k

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How to verify this limit?

calculus sequences-and-series

dec 8 at 22:11 Brian M. Scott 161k

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Order of $\mathrm{Aut}(G)$

group-theory

oct 7 at 22:10 Clive Newstead 15.4k

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Convergence of series $\sum\limits_{n=0}^\infty\frac{3n}{n!}$

calculus sequences-and-series

nov 29 at 18:23 André Nicolas 168k

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Additive quotient group $\mathbb{Q}/\mathbb{Z}$ is isomorphic to the multiplicative group of roots of unity

group-theory complex-numbers

aug 4 at 12:46 Georges Elencwajg 46.2k

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Analytic method for determining if a function is one-to-one

calculus algebra-precalculus functions

dec 28 '11 at 7:04 Asaf Karagila 95.9k

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How do I find the exact value of $\cos\frac{\pi}{12}\cos\frac{5\pi}{12}\cos\frac{7\pi}{12}\cos\frac{11\pi}{12}$?

trigonometry

jun 3 at 5:59 lab bhattacharjee 32.6k

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Are all limits solvable without L'Hospital Rule or Series Expansion

limit

may 13 at 22:44 Jon Claus 1,496

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Is this statement true for divisible Groups?

homework group-theory

may 8 '11 at 15:01 Jack Schmidt 22.8k

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Abelian group is the additive group $\mathbb{Q}$

group-theory

jun 14 at 17:26 Jared 7,535

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If $(|G|, |H|) > 1$, does it follow that $\operatorname{Aut}(G \times H) \neq \operatorname{Aut}(G) \times \operatorname{Aut}(H)$?

abstract-algebra group-theory finite-groups

2d ago anon 41.7k

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Intersection of the $p$-sylow and $q$-sylow subgroups of group $G$

abstract-algebra group-theory finite-groups

2d ago amWhy 61.5k

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if $A$ is Abelian group , $B$ is subgroup of $A$ , Is $B \times A/B \cong A$? [duplicate]

abstract-algebra group-theory vector-spaces finite-groups

1d ago amWhy 61.5k

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Properties of Equivalence Relation Compared with Equality

relations equivalence-relations

feb 23 at 17:16 Cameron Buie 30.4k

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