We prove the intermediate
claim HJne2:
J ≠ Empty.
An exact proof term for the current goal is HJne.
We prove the intermediate
claim HAeq:
A = {0}.
We prove the intermediate
claim Hlub0:
R_lub A 0.
rewrite the current goal using HAeq (from left to right).
An
exact proof term for the current goal is
R_lub_Sing0.
∎