[GAP Forum] about computing with integers mod n in GAP

[Pedro A. Garcia-Sanchez]

Dear Siddharta,

You can do many operations of integers mod n as if they were just 
integers. One way is to define your ring

R:=ZmodnZ(10);

and then you can set a name of its 'one'

one:=One(R);

 From this point, you can ask for the order of any integer mod 10:

gap> Order(3*one);
4

Or compute inverses

gap> 1/(3*one);
ZmodnZObj( 7, 10 )

 From these operations you can go back to "integers" with 'Int'

gap> Int(2/3*one);
4

I hope this helps.

Pedro


On 13/01/18 19:14, Siddhartha Sarkar wrote:
> Dear forum,
>
> I am trying to compute representations of elements in the finite ring of
> integers modulo n with given coefficients as powers of a given unit say k
> mod n. The coefficients need to be from some small interval of integers say
> [-t, t] (t is positive integer less than [n/2] so that t stays unique mod
> n).
>
> I was trying to find out list of all available commands in GAP which
> include finding multiplicative order of k mod n. Are there some list of all
> commands related to these?
>
> The online documentation of ZmodnZ doesn't have much information.
>
> Thanks,
> Siddhartha
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-- 
Pedro A. Garcia-Sanchez | www.ugr.es/~pedro