Set-Theoretic Concepts: Finite-Domain Functions

$q\times(q-1)\times(q-2)\times\cdots\times(q-p+1)$

$q\times(q-1)\times(q-2)\times\cdots\times1$

$q^p$

$p^q$

$q+(q-1)+(q-2)+\cdots+(q-p+1)$

$q+(q-1)+(q-2)+\cdots+1$

$p\times q$