Singular Manual: strand

| #### D.15.24.14 strand Procedure from library `tateProdCplxNegGrad.lib` (see tateProdCplxNegGrad_lib). Usage: strand(T,c,J) Purpose: compute the strand of T w.r.t. the set J and the vector c Return: subquotient complex of T which is the strand of T Example:
    LIB "tateProdCplxNegGrad.lib";
    intvec f = 1,1;
    def (S,E) = productOfProjectiveSpaces(f);
    intvec low = -3,-3;
    intvec high = 3,3;
    setring(S);
    module M = 0;
    intmat MGrading[2][1] = -1,-1;
    M = setModuleGrading(M,MGrading);
    multigradedcomplex tate;
    (E,tate) = tateResolution(M,low,high);
    setring(E);
    ring Z = cohomologyMatrixFromResolution(tate,low,high);
    setring(Z);
    print(cohomologymat);
    setring(E);
    intvec  c= 0,-3;
    intvec J = 1;
    multigradedcomplex U = strand(tate,c,J);
    U;
    Z = cohomologyMatrixFromResolution(U,low,high);
    setring(Z);
    print(cohomologymat);

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