Metamath Proof Explorer

Theorem sltasym

Description: Surreal less than is asymmetric. (Contributed by Scott Fenton, 16-Jun-2011)

Ref Expression
Assertion sltasym ⊢ A ∈ No ∧ B ∈ No → A < s B → ¬ B < s A

Proof

Step Hyp Ref Expression
1 sltso ⊢ < s Or No
2 soasym ⊢ < s Or No ∧ A ∈ No ∧ B ∈ No → A < s B → ¬ B < s A
3 1 2 mpan ⊢ A ∈ No ∧ B ∈ No → A < s B → ¬ B < s A