Theorem mnu0eld 44834

Description: A nonempty minimal universe contains the empty set. (Contributed by Rohan Ridenour, 13-Aug-2023.)

Hypotheses

Ref	Expression
mnu0eld.1	⊢ 𝑀 = {𝑘 ∣ ∀𝑙 ∈ 𝑘 (𝒫 𝑙 ⊆ 𝑘 ∧ ∀𝑚∃𝑛 ∈ 𝑘 (𝒫 𝑙 ⊆ 𝑛 ∧ ∀𝑝 ∈ 𝑙 (∃𝑞 ∈ 𝑘 (𝑝 ∈ 𝑞 ∧ 𝑞 ∈ 𝑚) → ∃𝑟 ∈ 𝑚 (𝑝 ∈ 𝑟 ∧ ∪ 𝑟 ⊆ 𝑛))))}
mnu0eld.2	⊢ (𝜑 → 𝑈 ∈ 𝑀)
mnu0eld.3	⊢ (𝜑 → 𝐴 ∈ 𝑈)

Assertion

Ref	Expression
mnu0eld	⊢ (𝜑 → ∅ ∈ 𝑈)

Distinct variable groups:   𝑈,𝑘,𝑚,𝑛,𝑟,𝑝,𝑙   𝑈,𝑞,𝑘,𝑚,𝑛,𝑝,𝑙

Allowed substitution hints:   𝜑(𝑘,𝑚,𝑛,𝑟,𝑞,𝑝,𝑙)   𝐴(𝑘,𝑚,𝑛,𝑟,𝑞,𝑝,𝑙)   𝑀(𝑘,𝑚,𝑛,𝑟,𝑞,𝑝,𝑙)

Proof of Theorem mnu0eld

Step	Hyp	Ref	Expression
1		mnu0eld.1	. 2 ⊢ 𝑀 = {𝑘 ∣ ∀𝑙 ∈ 𝑘 (𝒫 𝑙 ⊆ 𝑘 ∧ ∀𝑚∃𝑛 ∈ 𝑘 (𝒫 𝑙 ⊆ 𝑛 ∧ ∀𝑝 ∈ 𝑙 (∃𝑞 ∈ 𝑘 (𝑝 ∈ 𝑞 ∧ 𝑞 ∈ 𝑚) → ∃𝑟 ∈ 𝑚 (𝑝 ∈ 𝑟 ∧ ∪ 𝑟 ⊆ 𝑛))))}
2		mnu0eld.2	. 2 ⊢ (𝜑 → 𝑈 ∈ 𝑀)
3		mnu0eld.3	. 2 ⊢ (𝜑 → 𝐴 ∈ 𝑈)
4		0ss 4357	. . 3 ⊢ ∅ ⊆ 𝐴
5	4	a1i 11	. 2 ⊢ (𝜑 → ∅ ⊆ 𝐴)
6	1, 2, 3, 5	mnussd 44832	1 ⊢ (𝜑 → ∅ ∈ 𝑈)

Syntax hints:   → wi 4   ∧ wa 400  ∀wal 1561   = wceq 1563   ∈ wcel 2145  {cab 2743  ∀wral 3079  ∃wrex 3089   ⊆ wss 3907  ∅c0 4288  𝒫 cpw 4558  ∪ cuni 4867

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1818  ax-4 1832  ax-5 1933  ax-6 1990  ax-7 2031  ax-8 2147  ax-9 2155  ax-ext 2737  ax-sep 5250

This theorem depends on definitions:  df-bi 210  df-an 401  df-3an 1103  df-tru 1566  df-fal 1576  df-ex 1803  df-sb 2094  df-clab 2744  df-cleq 2757  df-clel 2840  df-ral 3080  df-rex 3090  df-rab 3418  df-v 3459  df-dif 3910  df-in 3914  df-ss 3924  df-nul 4289  df-pw 4560  df-uni 4868

This theorem is referenced by:  mnuprdlem4  44844