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5.1.70 kernel
Syntax:
kernel ( ring_name, map_name )
preimage ( ring_name, ideal_expression )
Type:
- ideal
Purpose:
- returns the kernel of a given map.
The second argument has to be a map from the basering to the given ring
(or an ideal defining such a map).
Example:
| ring r1=32003,(x,y,z,w),lp;
ring r=32003,(x,y,z),dp;
ideal i=x,y,z;
map f=r1,i;
setring r1;
// the kernel of f
kernel(r,f);
==> _[1]=w
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See
alg_kernel;
hom_kernel;
ideal;
map;
modulo;
preimage;
ring.
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