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D.2.4.2 katsura
Procedure from library poly.lib (see poly_lib).
- Usage:
katsura([n]): n integer
- Return:
katsura(n) : n-th katsura ideal of
(1) newly created and set ring (32003, x(0..n), dp), if nvars(basering) < n
(2) basering, if nvars(basering) >= n
katsura() : katsura ideal of basering
Example:
LIB "poly.lib"; ring r; basering; → // characteristic : 32003 → // number of vars : 3 → // block 1 : ordering dp → // : names x y z → // block 2 : ordering C katsura(); → _[1]=x+2y+2z-1 → _[2]=x2+2y2+2z2-x → _[3]=2xy+2yz-y katsura(4); basering; → _[1]=x(0)+2*x(1)+2*x(2)+2*x(3)-1 → _[2]=x(0)^2+2*x(1)^2+2*x(2)^2+2*x(3)^2-x(0) → _[3]=2*x(0)*x(1)+2*x(1)*x(2)+2*x(2)*x(3)-x(1) → _[4]=x(1)^2+2*x(0)*x(2)+2*x(1)*x(3)-x(2) → // characteristic : 32003 → // number of vars : 5 → // block 1 : ordering dp → // : names x(0) x(1) x(2) x(3) x(4) → // block 2 : ordering C |