Proof:We prove the intermediate claim L1: ∀X, Rng X → struct_b_b_e X.
Let X be given.
Assume HX.
Apply HX to the current goal.
Assume H _.
An exact proof term for the current goal is H.
An exact proof term for the current goal is MetaCat_struct_b_b_e_Forgetful_gen Rng L1.
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