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D.15.13.7 createTorsionFreeGroup
Procedure from librarymultigrading.lib (see multigrading_lib).
- Usage:
- createTorsionFreeGroup(S); S is an integer matrix
- Purpose:
- create the free subgroup generated by S within the
free Abelian group of rank nrows(S) - Return:
- group
LIB "multigrading.lib"; // ----------- extreme case ------------ // intmat S[1][3] = 1, -1, 10; // Torsion: intmat L[1][1] = 0; // The free subgroup generated by elements of S within Z^1 // can be constructed as follows: // shortcut: def G = createTorsionFreeGroup(S); printGroup(G); ==> Generators: ==> 1 -1 10 ==> Relations: ==> 0 // the general way: def GG = createGroup(S, L); // (S+L)/L printGroup(GG); ==> Generators: ==> 1 -1 10 ==> Relations: ==> 0 |