Theorem ssnel 4293

Description: Relationship between subset and elementhood. In the context of ordinals this can be seen as an ordering law. (Contributed by Jim Kingdon, 22-Jul-2019.)

Assertion

Ref	Expression
ssnel	|- ( A C_ B -> -. B e. A )

Proof of Theorem ssnel

Step	Hyp	Ref	Expression
1		elirr 4266	. 2 |- -. B e. B
2		ssel 2939	. 2 |- ( A C_ B -> ( B e. A -> B e. B ) )
3	1, 2	mtoi 590	1 |- ( A C_ B -> -. B e. A )

Syntax hints:   -. wn 3   -> wi 4   e. wcel 1393   C_ wss 2917

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-in1 544  ax-in2 545  ax-io 630  ax-5 1336  ax-7 1337  ax-gen 1338  ax-ie1 1382  ax-ie2 1383  ax-8 1395  ax-10 1396  ax-11 1397  ax-i12 1398  ax-bndl 1399  ax-4 1400  ax-17 1419  ax-i9 1423  ax-ial 1427  ax-i5r 1428  ax-ext 2022  ax-setind 4262

This theorem depends on definitions:  df-bi 110  df-3an 887  df-tru 1246  df-nf 1350  df-sb 1646  df-clab 2027  df-cleq 2033  df-clel 2036  df-nfc 2167  df-ne 2206  df-ral 2311  df-v 2559  df-dif 2920  df-in 2924  df-ss 2931  df-sn 3381

This theorem is referenced by:  nntri1  6074