isModule -- whether something is a module

• Usage:

  isModule M

• Inputs:
  • M, a thing
• Outputs:
  • a Boolean value, true if M is a module and false otherwise

i1 : R = QQ[a..d]/(a*b*c*d);

i2 : isModule R

o2 = false

i3 : M = a^2 * R^2 + a*b * R^2

o3 = image | a2 0  ab 0  |
           | 0  a2 0  ab |

                             2
o3 : R-module, submodule of R

i4 : isModule M

o4 = true