What I am looking for is an auto-like tactic that can prove simple equalities like:
1/2 = 2/4
So far, what I've tried manually is to use ring_simplify and field_simplify to prove equalities. Even this doesn't work out well (Coq 8.5b3). The example below works:
Require Export Coq.Reals.RIneq.
Local Open Scope Z_scope.
Local Open Scope R_scope.
Example test2: 1 = 1 / 1.
Proof. field_simplify. field_simplify. reflexivity.
Qed.
But it was necessary to use field_simplfy twice before reflexivity. The first field_simplfiy gives me:
1 subgoal
______________________________________(1/1)
1 / 1 = 1 / 1 / (1 / 1)
which is not subject to reflexivity.
The example below does not work, field_simplify seems to do nothing on the goal, and therefore, reflexivity can't be used.
Example test3: 1/2 = 2/4.
Proof. field_simplify. reflexivity.
Again, is there an automatic way to achieve this, like an field_auto?
I believe that tactic field is what you want.
Require Export Coq.Reals.RIneq.
Local Open Scope Z_scope.
Local Open Scope R_scope.
Example test3: 1/2 = 2/4.
Proof. field. Qed.
来源：https://stackoverflow.com/questions/34387573/how-to-automatically-prove-simple-equality-of-real-numbers-in-coq