You may want to say something about our branching conventions. In particular, the formula `lgamma(x) = log(gamma(x))` holds literally only in a cone near the positive real axis. Loggamma is the unique function `f(z)` on the complex numbers minus the non-positive integers satisfying the following properties:

- `f(z) = log(gamma(z))` for `z` positive real
- f is holomorphic on C minus the non-positive reals
- f is continuous on `{z in C | im(z) >= 0 and z not a non-positive integer}`

(you don't have to be as explicit, just don't say that lgamma(x)=log(gamma(x)))