possibleDenominators -- Possible denominators of deformations.

Synopsis

• Usage:
possibleDenominators(I)
possibleDenominators(I,v)
• Inputs:
• I, an ideal, monomial, reduced.
• v, a list, of variables of ring I.
• Outputs:

Description

Computes a list L of possible denominators of Laurent monomials representing FirstOrderDeformations of I. The list L is stratified into lists with ascending degree of the denominators. Each denominator is represented as a list of variables.

If the second argument v is given, one obtains only denominators contained (as a list) in v.

 i1 : R=QQ[x_0..x_4]; i2 : I=ideal(x_0*x_1,x_1*x_2,x_2*x_3,x_3*x_4,x_4*x_0); o2 : Ideal of R i3 : possibleDenominators(I) o3 = {{{x }, {x }, {x }, {x }, {x }}, {{x , x }, {x , x }, {x , x }, {x , 0 1 2 3 4 0 1 1 2 2 3 0 ------------------------------------------------------------------------ x }, {x , x }}} 4 3 4 o3 : List i4 : possibleDenominators(I,{x_0,x_1,x_2});