Theorem tskss 9580

Description: The subsets of an element of a Tarski class belong to the class. (Contributed by FL, 30-Dec-2010.) (Revised by Mario Carneiro, 18-Jun-2013.)

Assertion

Ref	Expression
tskss	|- ( ( T e. Tarski /\ A e. T /\ B C_ A ) -> B e. T )

Proof of Theorem tskss

Step	Hyp	Ref	Expression
1		elpw2g 4827	. . . 4 |- ( A e. T -> ( B e. ~P A <-> B C_ A ) )
2	1	adantl 482	. . 3 |- ( ( T e. Tarski /\ A e. T ) -> ( B e. ~P A <-> B C_ A ) )
3		tskpwss 9574	. . . 4 |- ( ( T e. Tarski /\ A e. T ) -> ~P A C_ T )
4	3	sseld 3602	. . 3 |- ( ( T e. Tarski /\ A e. T ) -> ( B e. ~P A -> B e. T ) )
5	2, 4	sylbird 250	. 2 |- ( ( T e. Tarski /\ A e. T ) -> ( B C_ A -> B e. T ) )
6	5	3impia 1261	1 |- ( ( T e. Tarski /\ A e. T /\ B C_ A ) -> B e. T )

Syntax hints:   -> wi 4   <-> wb 196   /\ wa 384   /\ w3a 1037   e. wcel 1990   C_ wss 3574   ~Pcpw 4158   Tarskictsk 9570

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-9 1999  ax-10 2019  ax-11 2034  ax-12 2047  ax-13 2246  ax-ext 2602  ax-sep 4781

This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3an 1039  df-tru 1486  df-ex 1705  df-nf 1710  df-sb 1881  df-clab 2609  df-cleq 2615  df-clel 2618  df-nfc 2753  df-ral 2917  df-rex 2918  df-rab 2921  df-v 3202  df-dif 3577  df-un 3579  df-in 3581  df-ss 3588  df-nul 3916  df-if 4087  df-pw 4160  df-sn 4178  df-pr 4180  df-op 4184  df-br 4654  df-tsk 9571

This theorem is referenced by:  tskin  9581  tsksn  9582  tsksuc  9584  tsk0  9585  tskr1om2  9590  tskint  9607