Metamath Proof Explorer


Theorem 2domtsk

Description: If a Tarski class is not empty, it has more than two elements. (Contributed by FL, 22-Feb-2011)

Ref Expression
Assertion 2domtsk TTarskiT2𝑜T

Proof

Step Hyp Ref Expression
1 tsk2 TTarskiT2𝑜T
2 tsksdom TTarski2𝑜T2𝑜T
3 1 2 syldan TTarskiT2𝑜T