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D.15.2.6 autX

Procedure from library autgradalg.lib (see autgradalg_lib).

Usage:
autX(RL, w, TOR); RL: ideal, w: intvec, TOR: optional list of integers.

Purpose:
compute generators for the hopf algebra O(Aut(X))
of the Mori dream space X given by Cox(X) := basering/RL and the ample class w.

Assume:
there is no torsion.

Return:
a ring. Also exports an ideal Iexported.

Example:
 
LIB "autgradalg.lib";
///////////////
//// CAREFUL: the following examples seems to be unfeasible at the moment, see remark in the paper
//echo=2;
///////////////
//// PP2
//intmat Q[1][4] =
//  1,1,1,1;
//ring R = 0,T(1..ncols(Q)),dp;
//// attach degree matrix Q to R:
//setBaseMultigrading(Q);
//ideal I = 0;
//intvec w0 = 1;
//def RR = autX(I, w0);
//setring RR;
//Iexported;
//basering;
//dim(std(Iexported));
//kill RR, Q, R;
///////////////
//// example 3.14 from the paper
//intmat Q[3][5] =
//  1,1,1,1,1,
//  1,-1,0,0,1,
//  1,1,1,0,0;
//list TOR = 2;
//ring R = 0,T(1..5),dp;
//// attach degree matrix Q to R:
//setBaseMultigrading(Q);
//ideal I = T(1)*T(2) + T(3)^2 + T(4)^2;
//list TOR = 2;
//intvec w0 = 2,1,0;
//def RR = autX(I, w0, TOR);
//setring RR;
//kill RR, Q, R;