isReflexive -- whether an ideal or module is reflexive

Synopsis

• Usage:

  isReflexive( I1 )

  isReflexive( M1 )

• Inputs:
  • I1, an ideal,
  • M1, a module,
• Optional inputs:
  • Strategy => a symbol, default value NoStrategy, specify a strategy for the internal call to reflexify
  • KnownDomain => a Boolean value, default value true, assume the ambient ring is a domain for the internal call to reflexify
• Outputs:
  • a Boolean value,

Description

i1 : R = QQ[x,y,z]/ideal(x^2-y*z);

i2 : m = ideal(x,y,z);

o2 : Ideal of R

i3 : isReflexive(m)

o3 = false

i4 : isReflexive(m*R^1)

o4 = false

i5 : I = ideal(x,y);

o5 : Ideal of R

i6 : isReflexive(I)

o6 = true

i7 : isReflexive(I*R^1)

o7 = true

See also

• reflexify -- calculate the double dual of an ideal or module Hom(Hom(M, R), R)
• Strategy -- an optional argument
• KnownDomain -- an option used to specify to certain functions that we know that the ring is a domain