combfunc.spad line 1 [edit on github]
CombinatorialOpsCategory is the category obtaining by adjoining summations and products to the usual combinatorial operations.
factorials(f)
rewrites the permutations and binomials in f
in terms of factorials.
factorials(f, x)
rewrites the permutations and binomials in f
involving x
in terms of factorials.
product(f(n), n = a..b)
returns f
(a) * ... * f
(b
) as a formal product.
product(f(n), n)
returns the formal product P
(n
) which verifies P
(n+1
)/P
(n
) = f
(n
).
summation(f(n), n = a..b)
returns f
(a) + ... + f
(b
) as a formal sum.
summation(f(n), n)
returns the formal sum S
(n
) which verifies S
(n+1
) - S
(n
) = f
(n
).