Ideal == ZZ -- equality

Ideal == ZZ -- equality

Synopsis:

Usage: I == n

Operator: == -- equality

Input:

I, an instance of class Ideal.

n, an instance of class ZZ: either 0, or 1.

Output:

n, an instance of class Thing: either 0, or 1.

If n==1, then determines whether I is the unit ideal. If n==0, then determines whether I is the zero ideal. Any other value for n is an error.

i1 : R = QQ[x];

i2 : ideal(x^2,x+1) == 1



o2 = true

i3 : ideal(0_R) == 0



o3 = true

Code:

     -- ../../../Macaulay2/m2/modules2.m2:358-364
     Ideal == ZZ := (I,n) -> (
          if n === 0
          then I.generators == 0
          else if n === 1
          then 1_(ring I) % I == 0
          else error "attempted to compare ideal to integer not 0 or 1"
          )