Metamath Proof Explorer


Definition df-ons

Description: Define the surreal ordinals. These are the maximum members of each generation of surreals. Variant of definition from Conway p. 27. (Contributed by Scott Fenton, 18-Mar-2025)

Ref Expression
Assertion df-ons ⊢ On s = x ∈ No | R ⁡ x = ∅

Detailed syntax breakdown

Step Hyp Ref Expression
0 cons class On s
1 vx setvar x
2 csur class No
3 cright class R
4 1 cv setvar x
5 4 3 cfv class R ⁡ x
6 c0 class ∅
7 5 6 wceq wff R ⁡ x = ∅
8 7 1 2 crab class x ∈ No | R ⁡ x = ∅
9 0 8 wceq wff On s = x ∈ No | R ⁡ x = ∅