tangentSpacePoint -- compute the complete intersection of quadrics in the tangent space at a given point

Synopsis

Usage:
(Z,phi) = tangentSpacePoint(point1,J,relPfaf)
Inputs:
- point1, an ideal, defining a point in the complete intersection of the four quadrics Q
- J, an ideal
- relPfaf, a matrix, a row matrix containing the four quadratic (Pfaffian) relations
Outputs:
- Z, an ideal, in the tangent space of Q at the given point
- phi, a ring map, from the coordinate ring of the P¹1 to the coordinate ring of the tangent space

Description

The tangent space of the complete intersection Q at a point p is a linear space isomorphic to a ℙ^k. We compute the projection of the complete intersection Q into this space and the polynomial map on coordinate rings corresponding to this projection. If a second ideal J is given, we compute the intersection of Q with the corresponding variety in T_p(Q).

Ways to use `tangentSpacePoint` :

tangentSpacePoint(Ideal,Ideal,Matrix)
tangentSpacePoint(Ideal,Matrix)

tangentSpacePoint -- compute the complete intersection of quadrics in the tangent space at a given point

Synopsis

Description

Ways to use tangentSpacePoint :

Ways to use `tangentSpacePoint` :