Theorem r1omtsk

Description: The set of hereditarily finite sets is a Tarski class. (The Tarski-Grothendieck Axiom is not needed for this theorem.) (Contributed by Mario Carneiro, 28-May-2013)

	Ref	Expression
Assertion	r1omtsk	|- ( R1 ` _om ) e. Tarski

Proof

Step	Hyp	Ref	Expression
1		omina	|- _om e. Inacc
2		inatsk	|- ( _om e. Inacc -> ( R1 ` _om ) e. Tarski )
3	1 2	ax-mp	|- ( R1 ` _om ) e. Tarski