I have an expression defined as
Ν[Δ_, l_] = FunctionExpand[((2^l (Δ + l - 1) Gamma[Δ + l - 1]^2 Gamma[Δ])/
(Gamma[Δ - 1] Gamma[(Δ + l)/2]^4 Gamma[1/8 - ((Δ - l)/2)]^2 *
Gamma[1/8 - ((2 - Δ - l)/2)]^2)),
Assumptions -> {Δ ∈ Integers, l ∈ Integers, Δ >= 0, l >= 0}];
The problem is that it diverges naively when I try to compute Ν[1,0]
with the divergence coming from the fact that Mathematica evaluates Ν[k,0]
to be
Ν[k, 0]
(* (2^(-4 + 2 k) (-1 + k)^2 Gamma[-(1/2) + k/2]^2)/(π Gamma[
1/8 - k/2]^2 Gamma[-(7/8) + k/2]^2 Gamma[k/2]^2) *)
Which means that the numerator becomes a product 0 ComplexInfinity
. But when I use FullSimplify
on the above, I get
Ν[k, 0] // FullSimplify
(* (4^(-1 + k) Gamma[(1 + k)/2]^2)/(π Gamma[
1/8 - k/2]^2 Gamma[-(7/8) + k/2]^2 Gamma[k/2]^2) *)
Is there a way to make Mathematica do this simplification by default? I am using this function in a sum, so I have to sum over $l = 0$ terms too, which is causing annoying errors.