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 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | omina | |
|
2 | inatsk | |
|
3 | 1 2 | ax-mp | |