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D.5.17.3 productVariety
Procedure from libraryschubert.lib (see schubert_lib).
- Usage:
- productVariety(U,V); U variety, V variety
- Input:
- two abstract varieties
- Output:
- a product variety as an abstract variety
- Return:
- variety
LIB "schubert.lib"; variety P = projectiveSpace(3); variety G = Grassmannian(2,4); variety W = productVariety(P,G); W; ==> A variety of dimension 7 ==> W.dimension == P.dimension + G.dimension; ==> 1 def r = W.baseRing; setring r; W.relations; ==> _[1]=h^4 ==> _[2]=q(1)^3-2*q(1)*q(2) ==> _[3]=q(1)^4-3*q(1)^2*q(2)+q(2)^2 |