Let z be given.
rewrite the current goal using
add_SNo_eq x Lx x Lx (from right to left).
Let m be given.
rewrite the current goal using Hm2 (from left to right).
rewrite the current goal using IH m Hm1 (from right to left).
We will
prove x + x < y + y.
We prove the intermediate
claim Lm:
m ∈ ω.
An
exact proof term for the current goal is
nat_p_trans n Hn m Hm1.
We prove the intermediate
claim Ly:
SNo y.
We prove the intermediate
claim Lxy:
x < y.
An exact proof term for the current goal is Hm1.
An
exact proof term for the current goal is
add_SNo_Lt3 x x y y Lx Lx Ly Ly Lxy Lxy.
∎