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 ∈ 𝐴 ∣ 𝐵 ∈ 𝑠}
elneldisjOLD.f	⊢ 𝑁 = {𝑠 ∈ 𝐴 ∣ 𝐵 ∉ 𝑠}

Assertion

Ref	Expression
elneldisjOLD	⊢ (𝐸 ∩ 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 ∈ 𝐴 ∣ 𝐵 ∈ 𝑠}
2		elneldisjOLD.f	. . . 4 ⊢ 𝑁 = {𝑠 ∈ 𝐴 ∣ 𝐵 ∉ 𝑠}
3		df-nel 2898	. . . . . 6 ⊢ (𝐵 ∉ 𝑠 ↔ ¬ 𝐵 ∈ 𝑠)
4	3	a1i 11	. . . . 5 ⊢ (𝑠 ∈ 𝐴 → (𝐵 ∉ 𝑠 ↔ ¬ 𝐵 ∈ 𝑠))
5	4	rabbiia 3185	. . . 4 ⊢ {𝑠 ∈ 𝐴 ∣ 𝐵 ∉ 𝑠} = {𝑠 ∈ 𝐴 ∣ ¬ 𝐵 ∈ 𝑠}
6	2, 5	eqtri 2644	. . 3 ⊢ 𝑁 = {𝑠 ∈ 𝐴 ∣ ¬ 𝐵 ∈ 𝑠}
7	1, 6	ineq12i 3812	. 2 ⊢ (𝐸 ∩ 𝑁) = ({𝑠 ∈ 𝐴 ∣ 𝐵 ∈ 𝑠} ∩ {𝑠 ∈ 𝐴 ∣ ¬ 𝐵 ∈ 𝑠})
8		rabnc 3962	. 2 ⊢ ({𝑠 ∈ 𝐴 ∣ 𝐵 ∈ 𝑠} ∩ {𝑠 ∈ 𝐴 ∣ ¬ 𝐵 ∈ 𝑠}) = ∅
9	7, 8	eqtri 2644	1 ⊢ (𝐸 ∩ 𝑁) = ∅

Syntax hints:  ¬ wn 3   ↔ wb 196   = wceq 1483   ∈ wcel 1990   ∉ wnel 2897  {crab 2916   ∩ 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)