DEFINITION next_plus_next()
TYPE =
∀g:G
.∀n:nat
.∀h:nat
.eq nat (next_plus g (next g n) h) (next g (next_plus g n h))
BODY =
assume g: G
assume n: nat
assume h: nat
(h1)
by (refl_equal . .)
we proved eq nat (next g (next_plus g n h)) (next g (next_plus g n h))
eq
nat
next_plus g n (plus (S O) h)
next g (next_plus g n h)
end of h1
(h2)
by (next_plus_assoc . . . .)
eq
nat
next_plus g (next_plus g n (S O)) h
next_plus g n (plus (S O) h)
end of h2
by (eq_ind_r . . . h1 . h2)
we proved
eq
nat
next_plus g (next_plus g n (S O)) h
next g (next_plus g n h)
that is equivalent to eq nat (next_plus g (next g n) h) (next g (next_plus g n h))
we proved
∀g:G
.∀n:nat
.∀h:nat
.eq nat (next_plus g (next g n) h) (next g (next_plus g n h))