Hi, It seems you are passing 0 and 1 literally to create the default field, in which case you will get the field of rationals, in which of course 1 + 1 = 2 <> 0.
You can't refer to the zero and one of GF(2) literally by 0 and 1. The zero is denoted by 0*Z(2), the one by Z(2)^0 (or also just by Z(2)). So the default field you want will be obtained by DefaultField( 0*Z(2), Z(2) ) FOr convenience you could just do o := 0*Z(2); e := Z(2); and then do your operations. Sandeep. Jianrong Li wrote:
Dear Sandeep, Thank you very much. But how to make the default field to be GF(2)? I use the command GF(2), and try 1+1, but it returns 2. With best wishes, Jianrong. 2012/12/31 Sandeep Murthy <sandeepr.mur...@gmail.com <mailto:sandeepr.mur...@gmail.com>> Hi, Creating finite fields is described in section 59.3 of the GAP reference manual. GaloisField(2) (also GF(2)) will get you the field of two elements 0,1. Sandeep. Jianrong Li wrote: Dear Forum, I want to work over the field F_2 with only two elements 0, 1. 1+1=0. I have matrices with entries 0, 1. The multiplication of the matrices are over F_2. I would like to define the default field as F_2. How could I do that in GAP? I tried DefaultField(Z(2)). But it seems that this doesn't work. Thank you very much. Best wishes, Jianrong. _________________________________________________ Forum mailing list Forum@mail.gap-system.org <mailto:Forum@mail.gap-system.org> http://mail.gap-system.org/__mailman/listinfo/forum <http://mail.gap-system.org/mailman/listinfo/forum>
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