Metamath Proof Explorer


Theorem tcid

Description: Defining property of the transitive closure function: it contains its argument as a subset. (Contributed by Mario Carneiro, 23-Jun-2013)

Ref Expression
Assertion tcid ⊢ A ∈ V → A ⊆ TC ⁡ A

Proof

Step Hyp Ref Expression
1 ssmin ⊢ A ⊆ ⋂ x | A ⊆ x ∧ Tr ⁡ x
2 tcvalg ⊢ A ∈ V → TC ⁡ A = ⋂ x | A ⊆ x ∧ Tr ⁡ x
3 1 2 sseqtrrid ⊢ A ∈ V → A ⊆ TC ⁡ A