Theorem bj-axemptylem 15692

Description: Lemma for bj-axempty 15693 and bj-axempty2 15694. (Contributed by BJ, 25-Oct-2020.) (Proof modification is discouraged.) Use ax-nul 4169 instead. (New usage is discouraged.)

Assertion

Ref	Expression
bj-axemptylem	⊢ ∃𝑥∀𝑦(𝑦 ∈ 𝑥 → ⊥)

Distinct variable group:   𝑥,𝑦

Proof of Theorem bj-axemptylem

Dummy variable 𝑧 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		bdfal 15633	. . 3 ⊢ BOUNDED ⊥
2	1	bdsep1 15685	. 2 ⊢ ∃𝑥∀𝑦(𝑦 ∈ 𝑥 ↔ (𝑦 ∈ 𝑧 ∧ ⊥))
3		biimp 118	. . . 4 ⊢ ((𝑦 ∈ 𝑥 ↔ (𝑦 ∈ 𝑧 ∧ ⊥)) → (𝑦 ∈ 𝑥 → (𝑦 ∈ 𝑧 ∧ ⊥)))
4		falimd 1387	. . . 4 ⊢ ((𝑦 ∈ 𝑧 ∧ ⊥) → ⊥)
5	3, 4	syl6 33	. . 3 ⊢ ((𝑦 ∈ 𝑥 ↔ (𝑦 ∈ 𝑧 ∧ ⊥)) → (𝑦 ∈ 𝑥 → ⊥))
6	5	alimi 1477	. 2 ⊢ (∀𝑦(𝑦 ∈ 𝑥 ↔ (𝑦 ∈ 𝑧 ∧ ⊥)) → ∀𝑦(𝑦 ∈ 𝑥 → ⊥))
7	2, 6	eximii 1624	1 ⊢ ∃𝑥∀𝑦(𝑦 ∈ 𝑥 → ⊥)

Syntax hints:   → wi 4   ∧ wa 104   ↔ wb 105  ∀wal 1370  ⊥wfal 1377  ∃wex 1514

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 615  ax-in2 616  ax-5 1469  ax-gen 1471  ax-ie1 1515  ax-ie2 1516  ax-4 1532  ax-ial 1556  ax-bd0 15613  ax-bdim 15614  ax-bdn 15617  ax-bdeq 15620  ax-bdsep 15684

This theorem depends on definitions:  df-bi 117  df-tru 1375  df-fal 1378

This theorem is referenced by:  bj-axempty  15693  bj-axempty2  15694