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5.13 GraphicSubgroupLattice for FpGroups, Information Menu

Placing the pointer inside a vertex (selected or not) and pressing the right mouse button pops up the ``Information'' menu. Clicking on any of the text lines will compute the corresponding property of the subgroup u associated with this vertex. Clicking on close will close the ``Information'' menu.

  • Index

    displays the index of u in the whole group.

  • IsNormal

    checks if u is normal in the whole group.

  • IsFpGroup

    checks if u is a finitely presented group. Note that a subgroup of a finitely presented group that is defined by a coset table or as kernel of an epimorphism is not automatically known to GAP as a finitely presented group. This means, that certain algorithms can not be applied. Use IsomorphismFpGroup (see IsomorphismFpGroup in the GAP reference manual) to calculate a finitely presented group and an isomorphism onto it, if some calculation does not work automatically.

  • Abelian Invariants

    computes and displays the abelian invariants of u.

  • Coset Table

    computes a coset table for u.

  • IsomorphismFpGroup

    computes a finitely presented group that is isomorphic to u and displays the number of generators and relators of it.

  • Factor Fp Group

    computes the factor group of the whole group by u, if u is normal.

    Note that the exact result of all these information displays is stored in the global variable LastResultOfInfoDisplay after each operation. So you can access this easily from the GAP command prompt. It is also returned as last value.

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    xgap manual
    Mai 2003