INT_REM_DOWN_CONV : conv
# let tm = `((x rem n) + (y rem n * &3) pow 2) rem n`;;
val tm : term = `(x rem n + (y rem n * &3) pow 2) rem n`
# INT_REM_DOWN_CONV tm;;
val it : thm =
|- (x rem n + (y rem n * &3) pow 2) rem n = (x + (y * &3) pow 2) rem n