Theorem elneldisjOLD 3965

Description: Obsolete version of elneldisj 3963 as of 17-Dec-2021. (Contributed by Alexander van der Vekens, 11-Jan-2018.) (Revised by AV, 9-Nov-2020.) (Proof modification is discouraged.) (New usage is discouraged.)

Hypotheses

Ref	Expression
elneldisjOLD.e	|- E = { s e. A | B e. s }
elneldisjOLD.f	|- N = { s e. A | B e/ s }

Assertion

Ref	Expression
elneldisjOLD	|- ( E i^i N ) = (/)

Distinct variable group:   A, s

Allowed substitution hints:   B( s)   E( s)   N( s)

Proof of Theorem elneldisjOLD

Step	Hyp	Ref	Expression
1		elneldisjOLD.e	. . 3 |- E = { s e. A | B e. s }
2		elneldisjOLD.f	. . . 4 |- N = { s e. A | B e/ s }
3		df-nel 2898	. . . . . 6 |- ( B e/ s <-> -. B e. s )
4	3	a1i 11	. . . . 5 |- ( s e. A -> ( B e/ s <-> -. B e. s ) )
5	4	rabbiia 3185	. . . 4 |- { s e. A | B e/ s } = { s e. A | -. B e. s }
6	2, 5	eqtri 2644	. . 3 |- N = { s e. A | -. B e. s }
7	1, 6	ineq12i 3812	. 2 |- ( E i^i N ) = ( { s e. A | B e. s } i^i { s e. A | -. B e. s } )
8		rabnc 3962	. 2 |- ( { s e. A | B e. s } i^i { s e. A | -. B e. s } ) = (/)
9	7, 8	eqtri 2644	1 |- ( E i^i N ) = (/)

Syntax hints:   -. wn 3   <-> wb 196   = wceq 1483   e. wcel 1990   e/ wnel 2897   {crab 2916   i^i cin 3573   (/)c0 3915

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

This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  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-nel 2898  df-ral 2917  df-rab 2921  df-v 3202  df-dif 3577  df-in 3581  df-nul 3916

This theorem is referenced by: (None)