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Program Zass_main

Usage

Zass_main 'file1' 'file2' ['file3'] ['file4'] [-s] [-c] [-d] [-t]

file1: matrix_TYP containing a presentation for G.
file2: bravais_TYP containing the unimodular group G.

Description

Determines isomorphism type of the cohomology group H^1(G,Q^n/Z^n), or in slight abuse of notation (since for finite G they are isomorphic) the group of extensions H²(G,Qⁿ/Zⁿ).

Options

-s    : writes the system of equations nessecary to
      : determine the H^1(G,**) to file3
-c    : writes the cocycles to file3.co or (or file4.co if
      : used together with -s) and the denomiantors to
      : file3.de (or file4.de respectively)
-d    : writes a different output format, which is meant for
      : developing other programs, so do not us this option.
-t    : give transformation matrix.

Remarks

See also for Extensions/Vector_systems and Presentation.

Examples

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