|
7.3.11 minres (plural)
Syntax:
minres ( list_expression )
Type:
- list
Syntax:
minres ( resolution_expression )
Type:
- resolution
Purpose:
- minimizes a free resolution of an ideal or module
given by the list_expression, resp. resolution_expression.
Example:
| LIB "ncalg.lib";
def A = makeUsl2();
setring A; // this algebra is U(sl_2)
ideal i=e,f,h;
i=std(i);
resolution F=nres(i,0); F;
==> 1 3 3 1
==> A <-- A <-- A <-- A
==>
==> 0 1 2 3
==> resolution not minimized yet
==>
print(matrix(F[1])); // print F's compactly
==> h,f,e
print(matrix(F[2]));
==> f, e, -1,
==> -h-2,0, e,
==> 0, -h+2,-f
print(matrix(F[3]));
==> e,
==> -f,
==> h
resolution MF=minres(F); MF;
==> 1 3 3 1
==> A <-- A <-- A <-- A
==>
==> 0 1 2 3
==>
print(matrix(MF[1]));
==> f,e
print(matrix(MF[2]));
==> -ef+2h+2,-e2,
==> f2, ef+h-2
print(matrix(MF[3]));
==> e,
==> -f
|
See
mres (plural);
nres (plural).
|