Let X, Tx, Y, Ty and f be given.
An exact proof term for the current goal is H.
We prove the intermediate
claim Hright:
∀V : set, V ∈ Ty → preimage_of X f V ∈ Tx.
We prove the intermediate
claim Hfun:
function_on f X Y.
Apply andI to the current goal.
Apply andI to the current goal.
An exact proof term for the current goal is Htops.
An exact proof term for the current goal is Hfun.
An exact proof term for the current goal is Hright.
∎