∀ a b c, (c + (b + a)) = ((b + c) + a)

Theorem assoc_plus1 : forall (a:nat), forall (b:nat), forall (c:nat), logic.eq (nat) (plus c (plus b a)) (plus (plus b c) a).

theorem assoc_plus1 : \forall (a:nat). \forall (b:nat). \forall (c:nat). (eq) (nat) ((plus) c ((plus) b a)) ((plus) ((plus) b c) a).

theorem assoc_plus1 : forall (a:nat.nat) , forall (b:nat.nat) , forall (c:nat.nat) , (((logic.eq_) (nat.nat)) ((((nat.plus) ) (c)) ((((nat.plus) ) (b)) (a)))) ((((nat.plus) ) ((((nat.plus) ) (b)) (c))) (a)).

assoc_plus1 : LEMMA (FORALL(a:nat_sttfa.sttfa_nat):(FORALL(b:nat_sttfa.sttfa_nat):(FORALL(c:nat_sttfa.sttfa_nat):logic_sttfa_th.eq[nat_sttfa.sttfa_nat](nat_sttfa.plus(c)(nat_sttfa.plus(b)(a)))(nat_sttfa.plus(nat_sttfa.plus(b)(c))(a)))))

Printing for OpenTheory is not working at the moment.