> < ^ Date: Tue, 10 Oct 2000 10:51:20 -0400 (EDT)
> < ^ From: Alexander Hulpke <hulpke@math.colostate.edu >
< ^ Subject: Re: MeatAxe

Dear GAP-Forum,

Jan Draisma asked:

I am running GAP4r2, and applied all bugfixes. I'd like to use the
MeatAxe, but even the following command yields an error message:

gap> GModuleByMats([ [[1,0],[0,1]] ],Rationals);            

Error matrices and field do not fit together or field is infinite at
Error( "matrices and field do not fit together or field is infinite" );
<function>( <arguments> ) called from read-eval-loop Entering break
read-eval-print loop, you can 'quit;' to quit to outer loop, or you can
return to continue

Well, the field is infinite allright, but I don't recall having this
problem in an earlier version. Am I overlooking something, or should I
use a different MeatAxe?

In earlier versions the test for finiteness of the field was not existent
and it is possible that the meataxe will have worked there as well.

However its underlying algorithms of the current implementation implicitly
assume finiteness of the field. The results they produce for inifinite
fields are unpredictable (and might be wrong) and the error message has been
put in to avoid this to happen.

(If you do not care about such problems, you can bypass the error message by
typing `return', but I would not want to give any guarantees about what
happens afterwards.)

At the moment, I believe there is no GAP4 implementation for a characteristic
zero meataxe available.



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