h.elsubst

强大的数学工具包

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                                *  elsubst  *
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        "element substitution"
        SYNTAX: X = elsubst(M, el, pz, ps)
                X = elsubst(V, el, pos)

        M is a matrix (m(i,j)) with 1 <= i <= m and 1 <=j <=n and V is 
        a vector (v(k)) with 1 <= k <= l.

        First case: X = elsubst(M, el, pz, ps).
        M = (m(i,j)) is a (m x n) matrix over Z, Q, Z/mZ, GF(p^n) (where
        p is a prime) or a number field, of polynomials over these 
        structures or of rational functions.
        1 <= pz <= m and 1 <= ps <= n.
        elsubst replaces the element m(pz, ps) by the value of el.
        X is assigned the result of this substitution.

        Second case: X = elsubst(V, el, pos).
        V = (v(k)) is a vector of length l over Z, Q, Z/mZ, GF(p^n) 
        (where p is a prime) or a number field, of polynomials over 
        these structures or of rational functions.
        1 <= pos <= l.
        elsubst replaces the element v(pos) by the value of el.
        X is assigned the result of this substitution.


        Example 1: (correct)

                elsubst({{x, y} {1/7, x/y}}, z, 1, 2)


        Example 2: (incorrect)

                elsubst({{x, y} {1/7, 0}}, z, 3, 2)

_ERR_NR_098
                

        Example 3: (incorrect)

                elsubst({x, y, 8}, {z}, 2)

_ERR_NR_077