CARAT Introduction / Programs / Invar_space

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## Program Invar_space

### Usage

    Invar_space 'file' [-a] [-s] [-e=n] [-d=n]

file: bravais_TYP containing a finite unimodular group G.

### Description

Calculates a Z-basis for the space of matrices with gtrAg = A for all g in G by a quick seminumerical algorithm with some random features. By default all symmetric invariant matrices are calculated.

### Options

    -a:      All invariant matrices are calculated.
    -s:      All skew-symmetric invariant matrices are calculated.
    -e=n:    Changes the default value of control parameter from 100 to n>100.
    -d=n:    The program will calculate n+1 elements F_0,..., F_n of the
             invariant space, then it calculates a Z-basis of the Q-span of
             F_0, ..., F_n intersected with Z^nxn.
             This option is only usefull if one knows the dimension of the
             space of invariant forms. By default this number is calculated
             by modular arithmetic.

### Remarks

See also for Form_space.

### Examples

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