Metamath Proof Explorer


Theorem noseqssno

Description: A surreal sequence is a subset of the surreals. (Contributed by Scott Fenton, 18-Apr-2025)

Ref Expression
Hypotheses noseq.1
|- ( ph -> Z = ( rec ( ( x e. _V |-> ( x +s 1s ) ) , A ) " _om ) )
noseq.2
|- ( ph -> A e. No )
Assertion noseqssno
|- ( ph -> Z C_ No )

Proof

Step Hyp Ref Expression
1 noseq.1
 |-  ( ph -> Z = ( rec ( ( x e. _V |-> ( x +s 1s ) ) , A ) " _om ) )
2 noseq.2
 |-  ( ph -> A e. No )
3 peano2no
 |-  ( y e. No -> ( y +s 1s ) e. No )
4 3 adantl
 |-  ( ( ph /\ y e. No ) -> ( y +s 1s ) e. No )
5 1 2 2 4 noseqind
 |-  ( ph -> Z C_ No )