| Step | Hyp | Ref
 | Expression | 
| 1 |   | ffn 5407 | 
. . . . . 6
⊢ (𝐹:(0...𝐾)⟶𝑉 → 𝐹 Fn (0...𝐾)) | 
| 2 | 1 | adantr 276 | 
. . . . 5
⊢ ((𝐹:(0...𝐾)⟶𝑉 ∧ 𝐾 ∈ ℕ0) → 𝐹 Fn (0...𝐾)) | 
| 3 |   | 0nn0 9264 | 
. . . . . . 7
⊢ 0 ∈
ℕ0 | 
| 4 | 3 | a1i 9 | 
. . . . . 6
⊢ ((𝐹:(0...𝐾)⟶𝑉 ∧ 𝐾 ∈ ℕ0) → 0 ∈
ℕ0) | 
| 5 |   | simpr 110 | 
. . . . . 6
⊢ ((𝐹:(0...𝐾)⟶𝑉 ∧ 𝐾 ∈ ℕ0) → 𝐾 ∈
ℕ0) | 
| 6 |   | nn0ge0 9274 | 
. . . . . . 7
⊢ (𝐾 ∈ ℕ0
→ 0 ≤ 𝐾) | 
| 7 | 6 | adantl 277 | 
. . . . . 6
⊢ ((𝐹:(0...𝐾)⟶𝑉 ∧ 𝐾 ∈ ℕ0) → 0 ≤
𝐾) | 
| 8 |   | elfz2nn0 10187 | 
. . . . . 6
⊢ (0 ∈
(0...𝐾) ↔ (0 ∈
ℕ0 ∧ 𝐾
∈ ℕ0 ∧ 0 ≤ 𝐾)) | 
| 9 | 4, 5, 7, 8 | syl3anbrc 1183 | 
. . . . 5
⊢ ((𝐹:(0...𝐾)⟶𝑉 ∧ 𝐾 ∈ ℕ0) → 0 ∈
(0...𝐾)) | 
| 10 |   | id 19 | 
. . . . . . 7
⊢ (𝐾 ∈ ℕ0
→ 𝐾 ∈
ℕ0) | 
| 11 |   | nn0re 9258 | 
. . . . . . . 8
⊢ (𝐾 ∈ ℕ0
→ 𝐾 ∈
ℝ) | 
| 12 | 11 | leidd 8541 | 
. . . . . . 7
⊢ (𝐾 ∈ ℕ0
→ 𝐾 ≤ 𝐾) | 
| 13 |   | elfz2nn0 10187 | 
. . . . . . 7
⊢ (𝐾 ∈ (0...𝐾) ↔ (𝐾 ∈ ℕ0 ∧ 𝐾 ∈ ℕ0
∧ 𝐾 ≤ 𝐾)) | 
| 14 | 10, 10, 12, 13 | syl3anbrc 1183 | 
. . . . . 6
⊢ (𝐾 ∈ ℕ0
→ 𝐾 ∈ (0...𝐾)) | 
| 15 | 14 | adantl 277 | 
. . . . 5
⊢ ((𝐹:(0...𝐾)⟶𝑉 ∧ 𝐾 ∈ ℕ0) → 𝐾 ∈ (0...𝐾)) | 
| 16 |   | fnimapr 5621 | 
. . . . 5
⊢ ((𝐹 Fn (0...𝐾) ∧ 0 ∈ (0...𝐾) ∧ 𝐾 ∈ (0...𝐾)) → (𝐹 “ {0, 𝐾}) = {(𝐹‘0), (𝐹‘𝐾)}) | 
| 17 | 2, 9, 15, 16 | syl3anc 1249 | 
. . . 4
⊢ ((𝐹:(0...𝐾)⟶𝑉 ∧ 𝐾 ∈ ℕ0) → (𝐹 “ {0, 𝐾}) = {(𝐹‘0), (𝐹‘𝐾)}) | 
| 18 | 17 | ineq1d 3363 | 
. . 3
⊢ ((𝐹:(0...𝐾)⟶𝑉 ∧ 𝐾 ∈ ℕ0) → ((𝐹 “ {0, 𝐾}) ∩ (𝐹 “ (1..^𝐾))) = ({(𝐹‘0), (𝐹‘𝐾)} ∩ (𝐹 “ (1..^𝐾)))) | 
| 19 | 18 | eqeq1d 2205 | 
. 2
⊢ ((𝐹:(0...𝐾)⟶𝑉 ∧ 𝐾 ∈ ℕ0) → (((𝐹 “ {0, 𝐾}) ∩ (𝐹 “ (1..^𝐾))) = ∅ ↔ ({(𝐹‘0), (𝐹‘𝐾)} ∩ (𝐹 “ (1..^𝐾))) = ∅)) | 
| 20 |   | disj 3499 | 
. . 3
⊢ (({(𝐹‘0), (𝐹‘𝐾)} ∩ (𝐹 “ (1..^𝐾))) = ∅ ↔ ∀𝑣 ∈ {(𝐹‘0), (𝐹‘𝐾)} ¬ 𝑣 ∈ (𝐹 “ (1..^𝐾))) | 
| 21 |   | simpl 109 | 
. . . . 5
⊢ ((𝐹:(0...𝐾)⟶𝑉 ∧ 𝐾 ∈ ℕ0) → 𝐹:(0...𝐾)⟶𝑉) | 
| 22 | 21, 9 | ffvelcdmd 5698 | 
. . . 4
⊢ ((𝐹:(0...𝐾)⟶𝑉 ∧ 𝐾 ∈ ℕ0) → (𝐹‘0) ∈ 𝑉) | 
| 23 | 21, 15 | ffvelcdmd 5698 | 
. . . 4
⊢ ((𝐹:(0...𝐾)⟶𝑉 ∧ 𝐾 ∈ ℕ0) → (𝐹‘𝐾) ∈ 𝑉) | 
| 24 |   | eleq1 2259 | 
. . . . . . 7
⊢ (𝑣 = (𝐹‘0) → (𝑣 ∈ (𝐹 “ (1..^𝐾)) ↔ (𝐹‘0) ∈ (𝐹 “ (1..^𝐾)))) | 
| 25 | 24 | notbid 668 | 
. . . . . 6
⊢ (𝑣 = (𝐹‘0) → (¬ 𝑣 ∈ (𝐹 “ (1..^𝐾)) ↔ ¬ (𝐹‘0) ∈ (𝐹 “ (1..^𝐾)))) | 
| 26 |   | df-nel 2463 | 
. . . . . 6
⊢ ((𝐹‘0) ∉ (𝐹 “ (1..^𝐾)) ↔ ¬ (𝐹‘0) ∈ (𝐹 “ (1..^𝐾))) | 
| 27 | 25, 26 | bitr4di 198 | 
. . . . 5
⊢ (𝑣 = (𝐹‘0) → (¬ 𝑣 ∈ (𝐹 “ (1..^𝐾)) ↔ (𝐹‘0) ∉ (𝐹 “ (1..^𝐾)))) | 
| 28 |   | eleq1 2259 | 
. . . . . . 7
⊢ (𝑣 = (𝐹‘𝐾) → (𝑣 ∈ (𝐹 “ (1..^𝐾)) ↔ (𝐹‘𝐾) ∈ (𝐹 “ (1..^𝐾)))) | 
| 29 | 28 | notbid 668 | 
. . . . . 6
⊢ (𝑣 = (𝐹‘𝐾) → (¬ 𝑣 ∈ (𝐹 “ (1..^𝐾)) ↔ ¬ (𝐹‘𝐾) ∈ (𝐹 “ (1..^𝐾)))) | 
| 30 |   | df-nel 2463 | 
. . . . . 6
⊢ ((𝐹‘𝐾) ∉ (𝐹 “ (1..^𝐾)) ↔ ¬ (𝐹‘𝐾) ∈ (𝐹 “ (1..^𝐾))) | 
| 31 | 29, 30 | bitr4di 198 | 
. . . . 5
⊢ (𝑣 = (𝐹‘𝐾) → (¬ 𝑣 ∈ (𝐹 “ (1..^𝐾)) ↔ (𝐹‘𝐾) ∉ (𝐹 “ (1..^𝐾)))) | 
| 32 | 27, 31 | ralprg 3673 | 
. . . 4
⊢ (((𝐹‘0) ∈ 𝑉 ∧ (𝐹‘𝐾) ∈ 𝑉) → (∀𝑣 ∈ {(𝐹‘0), (𝐹‘𝐾)} ¬ 𝑣 ∈ (𝐹 “ (1..^𝐾)) ↔ ((𝐹‘0) ∉ (𝐹 “ (1..^𝐾)) ∧ (𝐹‘𝐾) ∉ (𝐹 “ (1..^𝐾))))) | 
| 33 | 22, 23, 32 | syl2anc 411 | 
. . 3
⊢ ((𝐹:(0...𝐾)⟶𝑉 ∧ 𝐾 ∈ ℕ0) →
(∀𝑣 ∈ {(𝐹‘0), (𝐹‘𝐾)} ¬ 𝑣 ∈ (𝐹 “ (1..^𝐾)) ↔ ((𝐹‘0) ∉ (𝐹 “ (1..^𝐾)) ∧ (𝐹‘𝐾) ∉ (𝐹 “ (1..^𝐾))))) | 
| 34 | 20, 33 | bitrid 192 | 
. 2
⊢ ((𝐹:(0...𝐾)⟶𝑉 ∧ 𝐾 ∈ ℕ0) →
(({(𝐹‘0), (𝐹‘𝐾)} ∩ (𝐹 “ (1..^𝐾))) = ∅ ↔ ((𝐹‘0) ∉ (𝐹 “ (1..^𝐾)) ∧ (𝐹‘𝐾) ∉ (𝐹 “ (1..^𝐾))))) | 
| 35 | 19, 34 | bitrd 188 | 
1
⊢ ((𝐹:(0...𝐾)⟶𝑉 ∧ 𝐾 ∈ ℕ0) → (((𝐹 “ {0, 𝐾}) ∩ (𝐹 “ (1..^𝐾))) = ∅ ↔ ((𝐹‘0) ∉ (𝐹 “ (1..^𝐾)) ∧ (𝐹‘𝐾) ∉ (𝐹 “ (1..^𝐾))))) |