fact: Fixpoint prod_encode (p q : positive) : positive := match p, q with | 1, 1 => 1~1 | p~0, 1 => (prod_encode_fst p)~1~0 | p~1, 1 => (prod_encode_fst p)~1~1 | 1, q~0 => (prod_encode_snd q)~0~1 | 1, q~1 => (prod_encode_snd q)~1~1 | p~0, q~0 => (prod_encode p q)~0~0 | p~0, q~1 => (prod_encode p q)~1~0 | p~1, q~0 => (prod_encode p q)~0~1 | p~1, q~1 => (prod_encode p q)~1~1 end.
imports: Coq.QArith(QArith_base Qcanon) stdpp(well_founded) stdpp(options)