Theorem: Set.subset_union_right (GMLInit/Data/Set/Subset.lean)

State before:
α : Sort u_1
s✝ t✝ u s t : Set α
⊢ t.Subset (s.union t)
Tactic:
intro x ht
State after:
α : Sort u_1
s✝ t✝ u s t : Set α
x : α
ht : x ∈ t
⊢ x ∈ s.union t

State before:
α : Sort u_1
s✝ t✝ u s t : Set α
x : α
ht : x ∈ t
⊢ x ∈ s.union t
Tactic:
right
State after:
case h
α : Sort u_1
s✝ t✝ u s t : Set α
x : α
ht : x ∈ t
⊢ x ∈ t

State before:
case h
α : Sort u_1
s✝ t✝ u s t : Set α
x : α
ht : x ∈ t
⊢ x ∈ t
Tactic:
exact ht
State after:
no goals