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