We prove the intermediate
claim Hdefnet:
net0 = graph ω (λn : set ⇒ apply_fun seq n).
We prove the intermediate
claim HxX:
x ∈ X.
We prove the intermediate
claim Hnbhd:
∀U : set, U ∈ Tx → x ∈ U → ∃N : set, N ∈ ω ∧ ∀n : set, n ∈ ω → N ⊆ n → apply_fun seq n ∈ U.
rewrite the current goal using Hdefnet (from left to right).
We prove the intermediate
claim Hg:
∀n : set, n ∈ ω → apply_fun seq n ∈ X.
Let n be given.
An exact proof term for the current goal is (Hseq n Hn).
rewrite the current goal using Hdefnet (from left to right).
rewrite the current goal using Hdefnet (from left to right).
Apply and7I to the current goal.
An exact proof term for the current goal is HTx.
An exact proof term for the current goal is Htotnet.
An exact proof term for the current goal is Hgraphnet.
An exact proof term for the current goal is Hdomnet.
An exact proof term for the current goal is HxX.
Let U be given.
Apply (Hnbhd U HU HxU) to the current goal.
Let N be given.
We prove the intermediate
claim HNomega:
N ∈ ω.
An
exact proof term for the current goal is
(andEL (N ∈ ω) (∀n : set, n ∈ ω → N ⊆ n → apply_fun seq n ∈ U) HNpair).
We prove the intermediate
claim Hevent:
∀n : set, n ∈ ω → N ⊆ n → apply_fun seq n ∈ U.
An
exact proof term for the current goal is
(andER (N ∈ ω) (∀n : set, n ∈ ω → N ⊆ n → apply_fun seq n ∈ U) HNpair).
We use N to witness the existential quantifier.
Apply andI to the current goal.
An exact proof term for the current goal is HNomega.
Let i be given.
We prove the intermediate
claim HNsubi:
N ⊆ i.
We prove the intermediate
claim Hseqi:
apply_fun seq i ∈ U.
An exact proof term for the current goal is (Hevent i Hi HNsubi).
rewrite the current goal using Hdefnet (from left to right).
An exact proof term for the current goal is Hseqi.
We prove the intermediate
claim Hx:
x ∈ X.
Apply andI to the current goal.
Apply andI to the current goal.
Apply andI to the current goal.
An exact proof term for the current goal is HTx.
An exact proof term for the current goal is Hseq.
An exact proof term for the current goal is Hx.
Let U be given.
Apply (Hevent U HU HxU) to the current goal.
Let i0 be given.
We prove the intermediate
claim Hi0omega:
i0 ∈ ω.
We use i0 to witness the existential quantifier.
Apply andI to the current goal.
An exact proof term for the current goal is Hi0omega.
Let n be given.
An exact proof term for the current goal is Hi0subn.
An exact proof term for the current goal is (Hevent0 n Hn Hle).
rewrite the current goal using Hdef (from left to right).
rewrite the current goal using Happ (from right to left) at position 1.
An exact proof term for the current goal is Hnetn.
∎