We will prove apply_fun one_minus_fun 1 = 0.
We prove the intermediate claim H1R: 1 ∈ R.
An exact proof term for the current goal is real_1.
We prove the intermediate claim Hdef: one_minus_fun = graph R (λt0 : set ⇒ add_SNo 1 (minus_SNo t0)).
Use reflexivity.
rewrite the current goal using Hdef (from left to right).
rewrite the current goal using (apply_fun_graph R (λt0 : set ⇒ add_SNo 1 (minus_SNo t0)) 1 H1R) (from left to right).
rewrite the current goal using (add_SNo_minus_SNo_rinv 1 SNo_1) (from left to right).
Use reflexivity.
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