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Questions tagged [finite-groups]

Questions on group theory which concern finite groups.

11 questions from the last 30 days
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2 votes
0 answers
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Classification of centralizers of elements of finite simple groups of Lie type

I am currently studying the twisted Ree finite simple groups given by $^2G_2(3^{2n+1})$ and I was wondering if there is a reference for the classification of centralizers of elements in this family of ...
MAP's user avatar
  • 71
1 vote
1 answer
260 views

Group element of group algebra

For a prime $p$, let $G$ be a finite $p$-group and $F_{p}$ the field with $p$ elements. Let $A=\{a\in F_{p}G \mid a^{\sum_{x\in G}x}\neq 0\}$, where $F_pG$ is the group algebra of $G$ over $F_p$ and $...
gdre's user avatar
  • 171
12 votes
0 answers
339 views

Does every finite group have a small projective representation (over some ring)?

Question. Let $G$ be a finite group. Can we find some (commutative) ring $R$ and some positive integer $d=O(\log\lvert G\rvert)$ such that $G$ can be found as a subgroup of $\operatorname{PGL}_d(R)$? ...
Carl Schildkraut's user avatar
2 votes
0 answers
163 views

Nonabelian groups where every element has small order

Let $G$ be a finite nonabelian group with the property that if $g \in G$, then $$\DeclareMathOperator{\ord}{ord} \ord(g) \leqslant 10 \log_2 |G|, $$ where $\ord(g)$ is the order of the element $g$, ...
Anurag Sahay's user avatar
  • 1,354
0 votes
1 answer
65 views

Groups with $2$-transitive permutation representations of different degrees

Suppose $G$ is a finite group, and suppose that it acts $2$-transitively in each of the permutation representations $(G,X_i)$ ($i$ ranges over some index set $I$), where the $X_i$s all have different ...
THC's user avatar
  • 4,547
2 votes
2 answers
206 views

Software library for complex irreducible representations of $\mathrm{PSL}_n(q)$

I came across an extremely useful Python software library for the Monster group: https://github.com/Martin-Seysen/mmgroup which allows for all sorts of manipulations involving the sporadic finite ...
Fetchinson0234's user avatar
5 votes
1 answer
364 views

Groups with no proper non-trivial fully invariant subgroup

Let $G$ be a finite group. A subgroup $H$ of $G$ is said to be characteristic if $\phi(H)\subseteq H$, $\forall \phi \in \operatorname{Aut}(G)$ and fully invariant if $\phi(H)\subseteq H$, $\forall \...
Nick Belane's user avatar
5 votes
0 answers
85 views

Application of character sheaves to characters of $G(\mathbb{F}_q)$

I wish to ask about good examples of new applications of Lusztig's theory of character sheaves (and subsequent development, but excluding generalized Springer theory) back to the theory of characters ...
Cheng-Chiang Tsai's user avatar
2 votes
0 answers
100 views

Finite groups of Lie type

Table $22.1$ Finite groups of Lie type from "Linear algebraic groups and finite groups of Lie type" by Malle and Testerman: For the type $A$: $G_{sc}^{F}=\operatorname{SL}_{n}(q)$ and $G_{ad}...
scsnm's user avatar
  • 217
1 vote
1 answer
80 views

What are the efficient algorithms to compute Hamiltonian paths on Cayley graphs of finite groups ? Can GAP do it?

The famous Lovasz conjecture predicts existence of the Hamiltonian path on Cayley graphs. In general finding such a path is NP-complete problem, but there are many heuristic algorithms. Question 1: ...
Alexander Chervov's user avatar
8 votes
1 answer
1k views

GAP cannot solve Rubik's cube 4x4x4 and higher ? (Practical limits of Schreier–Sims algorithm)

According to our practical experiments and literature search - computer algebra system GAP cannot "solve" Rubik's cube 4x4x4 and higher. That means cannot decompose given random element of ...
Alexander Chervov's user avatar