Metamath Proof Explorer


Theorem clsk3nimkb

Description: If the base set is not empty, axiom K3 does not imply KB. A concrete example with a pseudo-closure function of k = ( x e. ~P b |-> ( b \ x ) ) is given. (Contributed by RP, 16-Jun-2021)

Ref Expression
Assertion clsk3nimkb ¬ ∀ 𝑏 ∀ 𝑘 ∈ ( 𝒫 𝑏 ↑m 𝒫 𝑏 ) ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) → ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) )

Proof

Step Hyp Ref Expression
1 1oex ⊢ 1o ∈ V
2 1n0 ⊢ 1o ≠ ∅
3 nelsn ⊢ ( 1o ≠ ∅ → ¬ 1o ∈ { ∅ } )
4 2 3 ax-mp ⊢ ¬ 1o ∈ { ∅ }
5 eldif ⊢ ( 1o ∈ ( V ∖ { ∅ } ) ↔ ( 1o ∈ V ∧ ¬ 1o ∈ { ∅ } ) )
6 ne0i ⊢ ( 1o ∈ ( V ∖ { ∅ } ) → ( V ∖ { ∅ } ) ≠ ∅ )
7 5 6 sylbir ⊢ ( ( 1o ∈ V ∧ ¬ 1o ∈ { ∅ } ) → ( V ∖ { ∅ } ) ≠ ∅ )
8 1 4 7 mp2an ⊢ ( V ∖ { ∅ } ) ≠ ∅
9 r19.2zb ⊢ ( ( V ∖ { ∅ } ) ≠ ∅ ↔ ( ∀ 𝑏 ∈ ( V ∖ { ∅ } ) ∃ 𝑘 ∈ ( 𝒫 𝑏 ↑m 𝒫 𝑏 ) ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) ∧ ¬ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ) → ∃ 𝑏 ∈ ( V ∖ { ∅ } ) ∃ 𝑘 ∈ ( 𝒫 𝑏 ↑m 𝒫 𝑏 ) ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) ∧ ¬ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ) ) )
10 8 9 mpbi ⊢ ( ∀ 𝑏 ∈ ( V ∖ { ∅ } ) ∃ 𝑘 ∈ ( 𝒫 𝑏 ↑m 𝒫 𝑏 ) ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) ∧ ¬ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ) → ∃ 𝑏 ∈ ( V ∖ { ∅ } ) ∃ 𝑘 ∈ ( 𝒫 𝑏 ↑m 𝒫 𝑏 ) ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) ∧ ¬ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ) )
11 rexex ⊢ ( ∃ 𝑏 ∈ ( V ∖ { ∅ } ) ∃ 𝑘 ∈ ( 𝒫 𝑏 ↑m 𝒫 𝑏 ) ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) ∧ ¬ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ) → ∃ 𝑏 ∃ 𝑘 ∈ ( 𝒫 𝑏 ↑m 𝒫 𝑏 ) ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) ∧ ¬ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ) )
12 rexanali ⊢ ( ∃ 𝑘 ∈ ( 𝒫 𝑏 ↑m 𝒫 𝑏 ) ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) ∧ ¬ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ) ↔ ¬ ∀ 𝑘 ∈ ( 𝒫 𝑏 ↑m 𝒫 𝑏 ) ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) → ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ) )
13 12 exbii ⊢ ( ∃ 𝑏 ∃ 𝑘 ∈ ( 𝒫 𝑏 ↑m 𝒫 𝑏 ) ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) ∧ ¬ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ) ↔ ∃ 𝑏 ¬ ∀ 𝑘 ∈ ( 𝒫 𝑏 ↑m 𝒫 𝑏 ) ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) → ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ) )
14 exnal ⊢ ( ∃ 𝑏 ¬ ∀ 𝑘 ∈ ( 𝒫 𝑏 ↑m 𝒫 𝑏 ) ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) → ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ) ↔ ¬ ∀ 𝑏 ∀ 𝑘 ∈ ( 𝒫 𝑏 ↑m 𝒫 𝑏 ) ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) → ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ) )
15 13 14 sylbb ⊢ ( ∃ 𝑏 ∃ 𝑘 ∈ ( 𝒫 𝑏 ↑m 𝒫 𝑏 ) ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) ∧ ¬ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ) → ¬ ∀ 𝑏 ∀ 𝑘 ∈ ( 𝒫 𝑏 ↑m 𝒫 𝑏 ) ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) → ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ) )
16 10 11 15 3syl ⊢ ( ∀ 𝑏 ∈ ( V ∖ { ∅ } ) ∃ 𝑘 ∈ ( 𝒫 𝑏 ↑m 𝒫 𝑏 ) ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) ∧ ¬ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ) → ¬ ∀ 𝑏 ∀ 𝑘 ∈ ( 𝒫 𝑏 ↑m 𝒫 𝑏 ) ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) → ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ) )
17 difelpw ⊢ ( 𝑏 ∈ ( V ∖ { ∅ } ) → ( 𝑏 ∖ 𝑥 ) ∈ 𝒫 𝑏 )
18 17 adantr ⊢ ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑥 ∈ 𝒫 𝑏 ) → ( 𝑏 ∖ 𝑥 ) ∈ 𝒫 𝑏 )
19 18 fmpttd ⊢ ( 𝑏 ∈ ( V ∖ { ∅ } ) → ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) : 𝒫 𝑏 ⟶ 𝒫 𝑏 )
20 pwexg ⊢ ( 𝑏 ∈ ( V ∖ { ∅ } ) → 𝒫 𝑏 ∈ V )
21 20 20 elmapd ⊢ ( 𝑏 ∈ ( V ∖ { ∅ } ) → ( ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ∈ ( 𝒫 𝑏 ↑m 𝒫 𝑏 ) ↔ ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) : 𝒫 𝑏 ⟶ 𝒫 𝑏 ) )
22 19 21 mpbird ⊢ ( 𝑏 ∈ ( V ∖ { ∅ } ) → ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ∈ ( 𝒫 𝑏 ↑m 𝒫 𝑏 ) )
23 simpllr ⊢ ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) → 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) )
24 difeq2 ⊢ ( 𝑥 = 𝑧 → ( 𝑏 ∖ 𝑥 ) = ( 𝑏 ∖ 𝑧 ) )
25 24 cbvmptv ⊢ ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) = ( 𝑧 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑧 ) )
26 23 25 eqtrdi ⊢ ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) → 𝑘 = ( 𝑧 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑧 ) ) )
27 difeq2 ⊢ ( 𝑧 = ( 𝑠 ∪ 𝑡 ) → ( 𝑏 ∖ 𝑧 ) = ( 𝑏 ∖ ( 𝑠 ∪ 𝑡 ) ) )
28 27 adantl ⊢ ( ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) ∧ 𝑧 = ( 𝑠 ∪ 𝑡 ) ) → ( 𝑏 ∖ 𝑧 ) = ( 𝑏 ∖ ( 𝑠 ∪ 𝑡 ) ) )
29 simplll ⊢ ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) → 𝑏 ∈ ( V ∖ { ∅ } ) )
30 simplr ⊢ ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) → 𝑠 ∈ 𝒫 𝑏 )
31 30 elpwid ⊢ ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) → 𝑠 ⊆ 𝑏 )
32 simpr ⊢ ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) → 𝑡 ∈ 𝒫 𝑏 )
33 32 elpwid ⊢ ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) → 𝑡 ⊆ 𝑏 )
34 31 33 unssd ⊢ ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) → ( 𝑠 ∪ 𝑡 ) ⊆ 𝑏 )
35 29 34 sselpwd ⊢ ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) → ( 𝑠 ∪ 𝑡 ) ∈ 𝒫 𝑏 )
36 vex ⊢ 𝑏 ∈ V
37 36 difexi ⊢ ( 𝑏 ∖ ( 𝑠 ∪ 𝑡 ) ) ∈ V
38 37 a1i ⊢ ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) → ( 𝑏 ∖ ( 𝑠 ∪ 𝑡 ) ) ∈ V )
39 26 28 35 38 fvmptd ⊢ ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) → ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) = ( 𝑏 ∖ ( 𝑠 ∪ 𝑡 ) ) )
40 difeq2 ⊢ ( 𝑧 = 𝑠 → ( 𝑏 ∖ 𝑧 ) = ( 𝑏 ∖ 𝑠 ) )
41 40 adantl ⊢ ( ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) ∧ 𝑧 = 𝑠 ) → ( 𝑏 ∖ 𝑧 ) = ( 𝑏 ∖ 𝑠 ) )
42 36 difexi ⊢ ( 𝑏 ∖ 𝑠 ) ∈ V
43 42 a1i ⊢ ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) → ( 𝑏 ∖ 𝑠 ) ∈ V )
44 26 41 30 43 fvmptd ⊢ ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) → ( 𝑘 ‘ 𝑠 ) = ( 𝑏 ∖ 𝑠 ) )
45 difeq2 ⊢ ( 𝑧 = 𝑡 → ( 𝑏 ∖ 𝑧 ) = ( 𝑏 ∖ 𝑡 ) )
46 45 adantl ⊢ ( ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) ∧ 𝑧 = 𝑡 ) → ( 𝑏 ∖ 𝑧 ) = ( 𝑏 ∖ 𝑡 ) )
47 36 difexi ⊢ ( 𝑏 ∖ 𝑡 ) ∈ V
48 47 a1i ⊢ ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) → ( 𝑏 ∖ 𝑡 ) ∈ V )
49 26 46 32 48 fvmptd ⊢ ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) → ( 𝑘 ‘ 𝑡 ) = ( 𝑏 ∖ 𝑡 ) )
50 44 49 uneq12d ⊢ ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = ( ( 𝑏 ∖ 𝑠 ) ∪ ( 𝑏 ∖ 𝑡 ) ) )
51 difindi ⊢ ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = ( ( 𝑏 ∖ 𝑠 ) ∪ ( 𝑏 ∖ 𝑡 ) )
52 50 51 eqtr4di ⊢ ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) )
53 39 52 sseq12d ⊢ ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) → ( ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) ↔ ( 𝑏 ∖ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) ) )
54 53 ralbidva ⊢ ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) → ( ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) ↔ ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑏 ∖ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) ) )
55 54 ralbidva ⊢ ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) → ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) ↔ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑏 ∖ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) ) )
56 52 eqeq1d ⊢ ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) → ( ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ↔ ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = 𝑏 ) )
57 56 imbi2d ⊢ ( ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) ∧ 𝑡 ∈ 𝒫 𝑏 ) → ( ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ↔ ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = 𝑏 ) ) )
58 57 ralbidva ⊢ ( ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) ∧ 𝑠 ∈ 𝒫 𝑏 ) → ( ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ↔ ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = 𝑏 ) ) )
59 58 ralbidva ⊢ ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) → ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ↔ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = 𝑏 ) ) )
60 59 notbid ⊢ ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) → ( ¬ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ↔ ¬ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = 𝑏 ) ) )
61 55 60 anbi12d ⊢ ( ( 𝑏 ∈ ( V ∖ { ∅ } ) ∧ 𝑘 = ( 𝑥 ∈ 𝒫 𝑏 ↦ ( 𝑏 ∖ 𝑥 ) ) ) → ( ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) ∧ ¬ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ) ↔ ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑏 ∖ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) ∧ ¬ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = 𝑏 ) ) ) )
62 pwidg ⊢ ( 𝑏 ∈ ( V ∖ { ∅ } ) → 𝑏 ∈ 𝒫 𝑏 )
63 ssidd ⊢ ( 𝑏 ∈ ( V ∖ { ∅ } ) → 𝑏 ⊆ 𝑏 )
64 eldifsnneq ⊢ ( 𝑏 ∈ ( V ∖ { ∅ } ) → ¬ 𝑏 = ∅ )
65 uneq1 ⊢ ( 𝑠 = 𝑏 → ( 𝑠 ∪ 𝑡 ) = ( 𝑏 ∪ 𝑡 ) )
66 65 eqeq1d ⊢ ( 𝑠 = 𝑏 → ( ( 𝑠 ∪ 𝑡 ) = 𝑏 ↔ ( 𝑏 ∪ 𝑡 ) = 𝑏 ) )
67 ssequn2 ⊢ ( 𝑡 ⊆ 𝑏 ↔ ( 𝑏 ∪ 𝑡 ) = 𝑏 )
68 66 67 bitr4di ⊢ ( 𝑠 = 𝑏 → ( ( 𝑠 ∪ 𝑡 ) = 𝑏 ↔ 𝑡 ⊆ 𝑏 ) )
69 ineq1 ⊢ ( 𝑠 = 𝑏 → ( 𝑠 ∩ 𝑡 ) = ( 𝑏 ∩ 𝑡 ) )
70 69 difeq2d ⊢ ( 𝑠 = 𝑏 → ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = ( 𝑏 ∖ ( 𝑏 ∩ 𝑡 ) ) )
71 70 eqeq1d ⊢ ( 𝑠 = 𝑏 → ( ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = 𝑏 ↔ ( 𝑏 ∖ ( 𝑏 ∩ 𝑡 ) ) = 𝑏 ) )
72 71 notbid ⊢ ( 𝑠 = 𝑏 → ( ¬ ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = 𝑏 ↔ ¬ ( 𝑏 ∖ ( 𝑏 ∩ 𝑡 ) ) = 𝑏 ) )
73 68 72 anbi12d ⊢ ( 𝑠 = 𝑏 → ( ( ( 𝑠 ∪ 𝑡 ) = 𝑏 ∧ ¬ ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = 𝑏 ) ↔ ( 𝑡 ⊆ 𝑏 ∧ ¬ ( 𝑏 ∖ ( 𝑏 ∩ 𝑡 ) ) = 𝑏 ) ) )
74 sseq1 ⊢ ( 𝑡 = 𝑏 → ( 𝑡 ⊆ 𝑏 ↔ 𝑏 ⊆ 𝑏 ) )
75 ineq2 ⊢ ( 𝑡 = 𝑏 → ( 𝑏 ∩ 𝑡 ) = ( 𝑏 ∩ 𝑏 ) )
76 inidm ⊢ ( 𝑏 ∩ 𝑏 ) = 𝑏
77 75 76 eqtrdi ⊢ ( 𝑡 = 𝑏 → ( 𝑏 ∩ 𝑡 ) = 𝑏 )
78 77 difeq2d ⊢ ( 𝑡 = 𝑏 → ( 𝑏 ∖ ( 𝑏 ∩ 𝑡 ) ) = ( 𝑏 ∖ 𝑏 ) )
79 difid ⊢ ( 𝑏 ∖ 𝑏 ) = ∅
80 78 79 eqtrdi ⊢ ( 𝑡 = 𝑏 → ( 𝑏 ∖ ( 𝑏 ∩ 𝑡 ) ) = ∅ )
81 80 eqeq1d ⊢ ( 𝑡 = 𝑏 → ( ( 𝑏 ∖ ( 𝑏 ∩ 𝑡 ) ) = 𝑏 ↔ ∅ = 𝑏 ) )
82 eqcom ⊢ ( ∅ = 𝑏 ↔ 𝑏 = ∅ )
83 81 82 bitrdi ⊢ ( 𝑡 = 𝑏 → ( ( 𝑏 ∖ ( 𝑏 ∩ 𝑡 ) ) = 𝑏 ↔ 𝑏 = ∅ ) )
84 83 notbid ⊢ ( 𝑡 = 𝑏 → ( ¬ ( 𝑏 ∖ ( 𝑏 ∩ 𝑡 ) ) = 𝑏 ↔ ¬ 𝑏 = ∅ ) )
85 74 84 anbi12d ⊢ ( 𝑡 = 𝑏 → ( ( 𝑡 ⊆ 𝑏 ∧ ¬ ( 𝑏 ∖ ( 𝑏 ∩ 𝑡 ) ) = 𝑏 ) ↔ ( 𝑏 ⊆ 𝑏 ∧ ¬ 𝑏 = ∅ ) ) )
86 73 85 rspc2ev ⊢ ( ( 𝑏 ∈ 𝒫 𝑏 ∧ 𝑏 ∈ 𝒫 𝑏 ∧ ( 𝑏 ⊆ 𝑏 ∧ ¬ 𝑏 = ∅ ) ) → ∃ 𝑠 ∈ 𝒫 𝑏 ∃ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 ∧ ¬ ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = 𝑏 ) )
87 62 62 63 64 86 syl112anc ⊢ ( 𝑏 ∈ ( V ∖ { ∅ } ) → ∃ 𝑠 ∈ 𝒫 𝑏 ∃ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 ∧ ¬ ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = 𝑏 ) )
88 rexanali ⊢ ( ∃ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 ∧ ¬ ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = 𝑏 ) ↔ ¬ ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = 𝑏 ) )
89 88 rexbii ⊢ ( ∃ 𝑠 ∈ 𝒫 𝑏 ∃ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 ∧ ¬ ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = 𝑏 ) ↔ ∃ 𝑠 ∈ 𝒫 𝑏 ¬ ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = 𝑏 ) )
90 rexnal ⊢ ( ∃ 𝑠 ∈ 𝒫 𝑏 ¬ ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = 𝑏 ) ↔ ¬ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = 𝑏 ) )
91 89 90 sylbb ⊢ ( ∃ 𝑠 ∈ 𝒫 𝑏 ∃ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 ∧ ¬ ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = 𝑏 ) → ¬ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = 𝑏 ) )
92 87 91 syl ⊢ ( 𝑏 ∈ ( V ∖ { ∅ } ) → ¬ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = 𝑏 ) )
93 inss1 ⊢ ( 𝑠 ∩ 𝑡 ) ⊆ 𝑠
94 ssun1 ⊢ 𝑠 ⊆ ( 𝑠 ∪ 𝑡 )
95 93 94 sstri ⊢ ( 𝑠 ∩ 𝑡 ) ⊆ ( 𝑠 ∪ 𝑡 )
96 sscon ⊢ ( ( 𝑠 ∩ 𝑡 ) ⊆ ( 𝑠 ∪ 𝑡 ) → ( 𝑏 ∖ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) )
97 95 96 ax-mp ⊢ ( 𝑏 ∖ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) )
98 97 rgen2w ⊢ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑏 ∖ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) )
99 92 98 jctil ⊢ ( 𝑏 ∈ ( V ∖ { ∅ } ) → ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑏 ∖ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) ∧ ¬ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( 𝑏 ∖ ( 𝑠 ∩ 𝑡 ) ) = 𝑏 ) ) )
100 22 61 99 rspcedvd ⊢ ( 𝑏 ∈ ( V ∖ { ∅ } ) → ∃ 𝑘 ∈ ( 𝒫 𝑏 ↑m 𝒫 𝑏 ) ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) ∧ ¬ ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) ) )
101 16 100 mprg ⊢ ¬ ∀ 𝑏 ∀ 𝑘 ∈ ( 𝒫 𝑏 ↑m 𝒫 𝑏 ) ( ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( 𝑘 ‘ ( 𝑠 ∪ 𝑡 ) ) ⊆ ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) → ∀ 𝑠 ∈ 𝒫 𝑏 ∀ 𝑡 ∈ 𝒫 𝑏 ( ( 𝑠 ∪ 𝑡 ) = 𝑏 → ( ( 𝑘 ‘ 𝑠 ) ∪ ( 𝑘 ‘ 𝑡 ) ) = 𝑏 ) )