The convert/factorial function converts GAMMAs (expressions expressed in terms of the gamma function), binomials and multinomial coefficients in an expression to factorials.

If an indeterminate or set of indeterminates is specified, then only GAMMAs and binomials involving a specified indeterminate are converted to the factorial function.

The convert(..., `!`) calling sequence is equivalent to the convert(..., factorial) calling sequence.

$\mathrm{convert}\left(\mathrm{\Gamma }\left(x\right)\,\mathrm{factorial}\right)$

$\left(x-1\right)!$

$\mathrm{convert}\left(\mathrm{\Gamma }\left(x\right)\,\mathrm{`!`}\right)$

$\left(x-1\right)!$

$\mathrm{convert}\left(\mathrm{binomial}\left(m\,3\right)\,\mathrm{factorial}\right)$

$\frac{m!}{6\left(m-3\right)!}$

$\mathrm{convert}\left(\mathrm{{\rm B}}\left(x\,y\right)\,\mathrm{factorial}\right)$

$\frac{\left(x-1\right)!\left(y-1\right)!}{\left(x+y-1\right)!}$