isConstant -- whether a ring element is constant

• Usage:

  isConstant f

• Inputs:
  • f
• Outputs:
  • whether f is constant, i.e., is in the coefficient ring

i1 : isConstant 3

o1 = true

i2 : QQ[a,b][x,y];

i3 : isConstant (x+a-x)

o3 = true

i4 : isConstant x

o4 = false

../../m2/rings.m2:103:26-103:66: --source code:
isConstant RingElement := r -> liftable(r, coefficientRing ring r)