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Implement 2-cohomology and module computations for arbitrary finite groups, not just solvable ones, via TwoCohomologyGeneric #3383

Merged
merged 6 commits into from
May 3, 2019
Merged

Implement 2-cohomology and module computations for arbitrary finite groups, not just solvable ones, via TwoCohomologyGeneric #3383

merged 6 commits into from
May 3, 2019

Commits on Apr 29, 2019

  1. ENHANCE: Two-Cohomology for arbitrary finite groups 

    Uses rewriting system since pc presentation will not always be available.

Use a rewriting system based on extensions for the factor group (as it is
smaller).
Rename `PresentationCocycle` to `FpGroupCocycle` and offer to calculate a
faithful permutation representation for it.

Added test

Add info from decomp.

Avoid the global Gpword fct. for order issues.

ENHANCE: Allow for different presentations for better rewriting

Added IsomorphismFpGroupForRewriting and method for alternating groups.

ENHANCE: Avoid duplicate test, build on existing permrep first.

Examples reflect new code. Make immutable.

Simplify presentation before trying permrep.

Force natural An for presentation.

REBASE: Fix wrong suggestion.

ENHANCE: Two-Cohomology for arbitrary finite groups

Uses rewriting system since pc presentation will not always be available.

Use a rewriting system based on extensions for the factor group (as it is
smaller).
Rename `PresentationCocycle` to `FpGroupCocycle` and offer to calculate a
faithful permutation representation for it.

Added test

Add info from decomp.

Avoid the global Gpword fct. for order issues.

ENHANCE: Allow for different presentations for better rewriting

Added IsomorphismFpGroupForRewriting and method for alternating groups.

ENHANCE: Avoid duplicate test, build on existing permrep first.

Examples reflect new code. Make immutable.

Simplify presentation before trying permrep.

Force natural An for presentation.

Simplify presentation before finding subgroup quotients

Run Tietze in LargerAbelianQuotient with different heuristics

ENHANCE: Two-Cohomology for arbitrary finite groups

Uses rewriting system since pc presentation will not always be available.

Use a rewriting system based on extensions for the factor group (as it is
smaller).
Rename `PresentationCocycle` to `FpGroupCocycle` and offer to calculate a
faithful permutation representation for it.

Added test

Add info from decomp.

Avoid the global Gpword fct. for order issues.

ENHANCE: Allow for different presentations for better rewriting

Added IsomorphismFpGroupForRewriting and method for alternating groups.

ENHANCE: Avoid duplicate test, build on existing permrep first.

Examples reflect new code. Make immutable.

Simplify presentation before trying permrep.

Force natural An for presentation.

REBASE: Fix wrong suggestion.

REBASE: Simplify presentation before finding subgroup quotients

Run Tietze in LargerAbelianQuotient with different heuristics
    @hulpke
    hulpke committed Apr 29, 2019
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  2. ENHANCE: Improvements to IrreducibleModules 

    Burnside-Brauer method for permutation groups.

Generically:
Factor out radical part stemming from P-core.
Spin submodules spanned by augmentation ideal vectors for first submodul
chain and chop, to avoid irreducibility tests in large regular module.

Also flag fix for `TrivialModule`.
    @hulpke
    hulpke committed Apr 29, 2019
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  3. ENHANCE: Homomorphisms for 1-dimensional modules just is common eigen… 

    …space.
    @hulpke
    hulpke committed Apr 29, 2019
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  4. ENHANCE: CompatiblePairs also works if group is not solvable 

    Uses Module isomorphism/automorphism code, modeled on Cannon/Holt autom.
group paper.

Also add action of compatible pairs
    @hulpke
    hulpke committed Apr 29, 2019
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  5. TWOCOHOM: Added tests: Construction of perfect groups 

    Includes action of compatible pairs on cohomology group and model.
    @hulpke
    hulpke committed Apr 29, 2019
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  6. CLEANUP: Replace tabs with blanks as requested

    @hulpke
    hulpke committed Apr 29, 2019
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