Singular Manual: makeLetterplaceRing

| ##### 7.7.10.0. makeLetterplaceRing Procedure from library `freegb.lib` (see freegb_lib). Usage: makeLetterplaceRing(d [,h]); d an integer, h an optional integer Return: ring Purpose: creates a ring with the ordering, used in letterplace computations Note: h = 0 (default) : Dp ordering will be used h = 2 : weights 1 used for all the variables, a tie breaker is a list of block of original ring h = 1 : the pure homogeneous letterplace block ordering (applicable in the situation of homogeneous input ideals) will be used. Example:
    LIB "freegb.lib";
    ring r = 0,(x,y,z),(dp(1),dp(2));
    def A = makeLetterplaceRing(2); // same as  makeLetterplaceRing(2,0)
    setring A;  A;
    ==> // coefficients: QQ
    ==> // number of vars : 6
    ==> //        block   1 : ordering Dp
    ==> //                  : names    x(1) y(1) z(1) x(2) y(2) z(2)
    ==> //        block   2 : ordering C
    ==> // letterplace ring
    attrib(A,"isLetterplaceRing");
    ==> 3
    attrib(A,"uptodeg");  // degree bound
    ==> 2
    setring r; def B = makeLetterplaceRing(2,1); // to compare:
    setring B;  B;
    ==> // coefficients: QQ
    ==> // number of vars : 6
    ==> //        block   1 : ordering lp
    ==> //                  : names    x(1)
    ==> //        block   2 : ordering dp
    ==> //                  : names    y(1) z(1)
    ==> //        block   3 : ordering lp
    ==> //                  : names    x(2)
    ==> //        block   4 : ordering dp
    ==> //                  : names    y(2) z(2)
    ==> //        block   5 : ordering C
    ==> // letterplace ring
    attrib(B,"isLetterplaceRing");
    ==> 3
    attrib(B,"uptodeg");  // degree bound
    ==> 2
    setring r; def C = makeLetterplaceRing(2,2); // to compare:
    setring C;  C;
    ==> // coefficients: QQ
    ==> // number of vars : 6
    ==> //        block   1 : ordering a
    ==> //                  : names    x(1) y(1) z(1) x(2) y(2) z(2)
    ==> //                  : weights     1    1    1    1    1    1
    ==> //        block   2 : ordering lp
    ==> //                  : names    x(1)
    ==> //        block   3 : ordering dp
    ==> //                  : names    y(1) z(1)
    ==> //        block   4 : ordering lp
    ==> //                  : names    x(2)
    ==> //        block   5 : ordering dp
    ==> //                  : names    y(2) z(2)
    ==> //        block   6 : ordering C
    ==> // letterplace ring
    attrib(C,"isLetterplaceRing");
    ==> 3
    attrib(C,"uptodeg");  // degree bound
    ==> 2

User manual for Singular version 4-1-1p3, 2018, generated by texi2html.