SumTools[Hypergeometric]
MultiplicativeDecomposition
construct the four minimal multiplicative decompositions of a hypergeometric term
Calling Sequence
Parameters
Description
Examples
References
MultiplicativeDecomposition[1](H, n, k)
MultiplicativeDecomposition[2](H, n, k)
MultiplicativeDecomposition[3](H, n, k)
MultiplicativeDecomposition[4](H, n, k)
H
-
hypergeometric term of n
n
variable
k
name
Let H be a hypergeometric term of n. The MultiplicativeDecomposition[i](H,n,k) calling sequence constructs the ith minimal multiplicative decomposition of H of the form Hn=Wn∏k=n0n−1Fk where Wn,Fn are rational functions of n, degreenumerFn and degreedenomFn have minimal possible values, for i=1,2,3,4.
If i=1 then degreedenomW is minimal.
If i=2 then degreenumerW is minimal.
If i=3 then degreenumerW+degreedenomW is minimal, and degreedenomW is minimal.
If i=4 then degreenumerW+degreedenomW is minimal, and degreenumerW is minimal.
If the MultiplicativeDecomposition command is called without an index, the first minimal multiplicative decomposition is constructed.
withSumToolsHypergeometric:
H≔24Productkk+2k−4+212k−3+212k+2+212k+11+212k−3k−22k+6k+12k−1+212k+1+212,k=4..n−1
H≔24∏k=4n−1kk+2k−4+2k−3+2k+2+2k+11+2k−3k−22k+6k+12k−1+2k+1+2
MultiplicativeDecomposition1H,n,k
n+1+22n−12n−22n+1nn+10+2n+9+2n+8+2n+7+2n+6+2n+5+2n+4+2n+3+2n+2+2n+2n−1+2∏k=4n−1k−4+2k−3+2k+12k+6k−3305+2214+213+212+211+210+29+28+27+26+24+23+2
MultiplicativeDecomposition2H,n,k
158176291553280002+221+224+23+22∏k=4n−1k+2+2k+11+2k−3k−22n−2+22n−3+22n+52n+42n+32n+22n+2n−1+2n−4+2n+11n+10n+9n+8n+7n+6n+1n
MultiplicativeDecomposition3H,n,k
2+21+2n+1+2n−12n−22n+1n∏k=4n−1k−4+2k+11+2k+12k+6k−3305+2n−2+2n−3+2
MultiplicativeDecomposition4H,n,k
120962+21+2n+1+2n−1n−2∏k=4n−1k−4+2k+11+2k−3k−2k+125+2n−2+2n−3+2n+5n+4n+3n+2
Abramov, S.A.; Le, H.Q.; and Petkovsek, M. "Rational Canonical Forms and Efficient Representations of Hypergeometric Terms." Proc. ISSAC 2003, pp. 7-14. 2003.
See Also
SumTools[Hypergeometric][EfficientRepresentation]
SumTools[Hypergeometric][RationalCanonicalForm]
SumTools[Hypergeometric][SumDecomposition]
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