Identity and Isomorphism

Incidence structures D₁ = (P₁, B₁, I₁) and D₂ = (P₂, B₂, I₂) are identical if P₁ = P₂, B₁ = B₂ and I₁ = I₂.

D eq E : Inc, Inc -> BoolElt

Return true if the incidence structures D and E are identical, otherwise false.

D ne E : Inc, Inc -> BoolElt

Return true if the incidence structures D and E are not identical, otherwise false.

IsIsomorphic(D, E: parameters) : Inc, Inc -> BoolElt, Map

    AutomorphismGroups: MonStgElt       Default: "None"

Return true if the incidence structures D and E are isomorphic, otherwise false. If they are isomorphic, then an isomorphism is returned as the second value. The function first computes none, one, or both of the automorphism groups of the left and right incidence structures. In difficult examples, this may significantly speed up testing for isomorphism. The parameter AutomorphismGroups, with valid string values "Both", "Left", "Right", "None", may be used to specify which of the automorphism groups should be constructed if not already known. The default is "None".