[GAP Forum] magnitude in GAP

[Alexander Hulpke]

Dear Forum, Dear Saad Awaid,

> I am trying to write some code to  find Z(chi);
>
> where   Z(\chi ) = \{ g \in G\left| {\left| {\chi (g)} \right| =  
> \chi (1)\} } \right
>
> it seems that GAP doesn't contain function to find the magnitude  
> for  complex number?

|x|^2=x* conjugate(x), complex conjugate denoted by
GaloisCyc(x,-1);

Thus you could check whether chi[g]*GaloisCyc(chi[g],-1)=chi[1]^2

If chi is a proper class function, you also coud simply use
CenterOfCharacter
instead of writing your own function.

Best,

    Alexander Hulpke


-- Colorado State University, Department of Mathematics,
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