I'm trying to prove the following trivial lemma:
Lemma lt_or_ge: forall a b : nat,
((a <? b) = false) -> (b <= a).
Proof.
intros a0 b0 H.
I need something like:
((a <? b) = false) -> (a >= b)
But can't seem to find it in Coq libraries. Any help is appreciated, thanks.
The Search
command only takes into account imported modules, meaning you need to you import Arith
module to get access to a number of useful (and now searchable) lemmas.
A search query like the following one
From Coq Require Import Arith.
(* queries separated by whitespace mean boolean "and" *)
Search (_ <? _) false (_ <= _).
will get you what you need right away:
lt_or_ge: forall a b : nat, (a <? b) = false -> b <= a
Nat.ltb_ge: forall x y : nat, (x <? y) = false <-> y <= x