Macaulay2 » Documentation
Packages » OIGroebnerBases > ranks
next | previous | forward | backward | up | index | toc

ranks -- display the ranks of an OI-resolution

Synopsis

Description

Given an OI-resolution $C$, this method displays the ranks of the modules in $C$.

i1 : P = makePolynomialOIAlgebra(2, x, QQ);
i2 : F = makeFreeOIModule(e, {1,1}, P);
i3 : installGeneratorsInWidth(F, 2);
i4 : b = x_(1,2)*x_(1,1)*e_(2,{2},1)+x_(2,2)*x_(2,1)*e_(2,{1},2);
i5 : C = oiRes({b}, 2)

o5 = 0: (e0, {2}, {-2})
     1: (e1, {4}, {-4})
     2: (e2, {5, 5, 5}, {-5, -5, -5})

o5 : OIResolution
i6 : ranks C

o6 = 0: rank 1
     1: rank 1
     2: rank 3

Ways to use ranks :

For the programmer

The object ranks is a method function.