RegularChains[FastArithmeticTools][IteratedResultantDim1] - iterated resultant of a polynomial w.r.t a one-dim regular chain
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Calling Sequence
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IteratedResultantDim1(f, rc, R, v)
IteratedResultantDim1(f, rc, R, v, bound)
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Parameters
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R
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a polynomial ring
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rc
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a regular chain
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f
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a polynomial
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v
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variable of R
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bound
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an upper bound of the degree of the iterated resultant to be computed (optional)
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Description
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The function call IteratedResultantDim1(f, rc, R) returns the numerator of the iterated resultant of f w.r.t. rc, computed over the field of univariate rational functions in v and with coefficients in R. See the command IteratedResultant for a definition of the notion of an iterated resultant.
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rc is assumed to be a one-dimensional normalized regular chain with v as free variable and f has positive degree w.r.t. v.
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The default value of bound is the product of the total degrees of the polynomials in rc and f.
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The iterated resultant computed by the command IteratedResultant produces the same answer provided that all initials in the regular chain rc are equal to .
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The interest of the function call IteratedResultantDim1(f, rc, R) resides in the fact that, if the polynomial f is regular modulo the saturated ideal of the regular chain rc, then the roots of the returned polynomial form the projection on the v-axis of the intersection of the hypersurface defined by f and the quasi-component defined by rc.
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Examples
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Define a ring of polynomials.
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Define random dense polynomial and regular chain of R.
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Compute the (numerator) of the iterated resultant
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Compare with the generic algorithm (non-fast and non-modular algorithm) of the command IteratedResultant.
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Check that the two results are equal, since here all initials are equal to 1.
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Download Help Document
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