Definition df-old 31931

Description: Define the older than function. This function carries an ordinal to all surreals made by a previous ordinal. (Contributed by Scott Fenton, 17-Dec-2021.)

Assertion

Ref	Expression
df-old	|- O = ( x e. On |-> U. ( M " x ) )

Detailed syntax breakdown of Definition df-old

Step	Hyp	Ref	Expression
1		cold 31926	. 2 class O
2		vx	. . 3 setvar x
3		con0 5723	. . 3 class On
4		cmade 31925	. . . . 5 class M
5	2	cv 1482	. . . . 5 class x
6	4, 5	cima 5117	. . . 4 class ( M " x )
7	6	cuni 4436	. . 3 class U. ( M " x )
8	2, 3, 7	cmpt 4729	. 2 class ( x e. On |-> U. ( M " x ) )
9	1, 8	wceq 1483	1 wff O = ( x e. On |-> U. ( M " x ) )

This definition is referenced by: (None)