| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | orc 868 | . . . . . . 7
⊢ (𝑣 = 𝑁 → (𝑣 = 𝑁 ∨ ((𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒)) ↔ (𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ∨ (𝑣 = 𝑁 ∧ 𝑒 = {𝑣})))))) | 
| 2 | 1 | a1d 25 | . . . . . 6
⊢ (𝑣 = 𝑁 → (𝑁 ∈ 𝑉 → (𝑣 = 𝑁 ∨ ((𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒)) ↔ (𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ∨ (𝑣 = 𝑁 ∧ 𝑒 = {𝑣}))))))) | 
| 3 |  | simpl 482 | . . . . . . . . . . . . . . 15
⊢ ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑉) → 𝑣 ≠ 𝑁) | 
| 4 | 3 | anim1i 615 | . . . . . . . . . . . . . 14
⊢ (((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑉) ∧ (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒)) → (𝑣 ≠ 𝑁 ∧ (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒))) | 
| 5 |  | 3anass 1095 | . . . . . . . . . . . . . 14
⊢ ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ↔ (𝑣 ≠ 𝑁 ∧ (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒))) | 
| 6 | 4, 5 | sylibr 234 | . . . . . . . . . . . . 13
⊢ (((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑉) ∧ (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒)) → (𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒)) | 
| 7 | 6 | orcd 874 | . . . . . . . . . . . 12
⊢ (((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑉) ∧ (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒)) → ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ∨ (𝑣 = 𝑁 ∧ 𝑒 = {𝑣}))) | 
| 8 | 7 | ex 412 | . . . . . . . . . . 11
⊢ ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑉) → ((𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) → ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ∨ (𝑣 = 𝑁 ∧ 𝑒 = {𝑣})))) | 
| 9 |  | 3simpc 1151 | . . . . . . . . . . . . 13
⊢ ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) → (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒)) | 
| 10 | 9 | a1i 11 | . . . . . . . . . . . 12
⊢ ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑉) → ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) → (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒))) | 
| 11 |  | vsnid 4663 | . . . . . . . . . . . . . . . . 17
⊢ 𝑣 ∈ {𝑣} | 
| 12 |  | eleq2 2830 | . . . . . . . . . . . . . . . . 17
⊢ (𝑒 = {𝑣} → (𝑣 ∈ 𝑒 ↔ 𝑣 ∈ {𝑣})) | 
| 13 | 11, 12 | mpbiri 258 | . . . . . . . . . . . . . . . 16
⊢ (𝑒 = {𝑣} → 𝑣 ∈ 𝑒) | 
| 14 | 13 | adantl 481 | . . . . . . . . . . . . . . 15
⊢ ((𝑣 = 𝑁 ∧ 𝑒 = {𝑣}) → 𝑣 ∈ 𝑒) | 
| 15 |  | eleq1 2829 | . . . . . . . . . . . . . . . 16
⊢ (𝑣 = 𝑁 → (𝑣 ∈ 𝑒 ↔ 𝑁 ∈ 𝑒)) | 
| 16 | 15 | adantr 480 | . . . . . . . . . . . . . . 15
⊢ ((𝑣 = 𝑁 ∧ 𝑒 = {𝑣}) → (𝑣 ∈ 𝑒 ↔ 𝑁 ∈ 𝑒)) | 
| 17 | 14, 16 | mpbid 232 | . . . . . . . . . . . . . 14
⊢ ((𝑣 = 𝑁 ∧ 𝑒 = {𝑣}) → 𝑁 ∈ 𝑒) | 
| 18 | 17, 14 | jca 511 | . . . . . . . . . . . . 13
⊢ ((𝑣 = 𝑁 ∧ 𝑒 = {𝑣}) → (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒)) | 
| 19 | 18 | a1i 11 | . . . . . . . . . . . 12
⊢ ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑉) → ((𝑣 = 𝑁 ∧ 𝑒 = {𝑣}) → (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒))) | 
| 20 | 10, 19 | jaod 860 | . . . . . . . . . . 11
⊢ ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑉) → (((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ∨ (𝑣 = 𝑁 ∧ 𝑒 = {𝑣})) → (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒))) | 
| 21 | 8, 20 | impbid 212 | . . . . . . . . . 10
⊢ ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑉) → ((𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ↔ ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ∨ (𝑣 = 𝑁 ∧ 𝑒 = {𝑣})))) | 
| 22 | 21 | rexbidv 3179 | . . . . . . . . 9
⊢ ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑉) → (∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ↔ ∃𝑒 ∈ 𝐸 ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ∨ (𝑣 = 𝑁 ∧ 𝑒 = {𝑣})))) | 
| 23 | 22 | anbi2d 630 | . . . . . . . 8
⊢ ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑉) → ((𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒)) ↔ (𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ∨ (𝑣 = 𝑁 ∧ 𝑒 = {𝑣}))))) | 
| 24 | 23 | olcd 875 | . . . . . . 7
⊢ ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑉) → (𝑣 = 𝑁 ∨ ((𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒)) ↔ (𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ∨ (𝑣 = 𝑁 ∧ 𝑒 = {𝑣})))))) | 
| 25 | 24 | ex 412 | . . . . . 6
⊢ (𝑣 ≠ 𝑁 → (𝑁 ∈ 𝑉 → (𝑣 = 𝑁 ∨ ((𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒)) ↔ (𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ∨ (𝑣 = 𝑁 ∧ 𝑒 = {𝑣}))))))) | 
| 26 | 2, 25 | pm2.61ine 3025 | . . . . 5
⊢ (𝑁 ∈ 𝑉 → (𝑣 = 𝑁 ∨ ((𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒)) ↔ (𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ∨ (𝑣 = 𝑁 ∧ 𝑒 = {𝑣})))))) | 
| 27 |  | orbidi 955 | . . . . 5
⊢ ((𝑣 = 𝑁 ∨ ((𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒)) ↔ (𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ∨ (𝑣 = 𝑁 ∧ 𝑒 = {𝑣}))))) ↔ ((𝑣 = 𝑁 ∨ (𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒))) ↔ (𝑣 = 𝑁 ∨ (𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ∨ (𝑣 = 𝑁 ∧ 𝑒 = {𝑣})))))) | 
| 28 | 26, 27 | sylib 218 | . . . 4
⊢ (𝑁 ∈ 𝑉 → ((𝑣 = 𝑁 ∨ (𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒))) ↔ (𝑣 = 𝑁 ∨ (𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ∨ (𝑣 = 𝑁 ∧ 𝑒 = {𝑣})))))) | 
| 29 |  | elun 4153 | . . . . 5
⊢ (𝑣 ∈ ({𝑁} ∪ {𝑛 ∈ 𝑉 ∣ ∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒)}) ↔ (𝑣 ∈ {𝑁} ∨ 𝑣 ∈ {𝑛 ∈ 𝑉 ∣ ∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒)})) | 
| 30 |  | velsn 4642 | . . . . . 6
⊢ (𝑣 ∈ {𝑁} ↔ 𝑣 = 𝑁) | 
| 31 |  | eleq1 2829 | . . . . . . . . 9
⊢ (𝑛 = 𝑣 → (𝑛 ∈ 𝑒 ↔ 𝑣 ∈ 𝑒)) | 
| 32 | 31 | anbi2d 630 | . . . . . . . 8
⊢ (𝑛 = 𝑣 → ((𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒) ↔ (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒))) | 
| 33 | 32 | rexbidv 3179 | . . . . . . 7
⊢ (𝑛 = 𝑣 → (∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒) ↔ ∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒))) | 
| 34 | 33 | elrab 3692 | . . . . . 6
⊢ (𝑣 ∈ {𝑛 ∈ 𝑉 ∣ ∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒)} ↔ (𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒))) | 
| 35 | 30, 34 | orbi12i 915 | . . . . 5
⊢ ((𝑣 ∈ {𝑁} ∨ 𝑣 ∈ {𝑛 ∈ 𝑉 ∣ ∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒)}) ↔ (𝑣 = 𝑁 ∨ (𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒)))) | 
| 36 | 29, 35 | bitri 275 | . . . 4
⊢ (𝑣 ∈ ({𝑁} ∪ {𝑛 ∈ 𝑉 ∣ ∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒)}) ↔ (𝑣 = 𝑁 ∨ (𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒)))) | 
| 37 |  | elun 4153 | . . . . 5
⊢ (𝑣 ∈ ({𝑁} ∪ {𝑛 ∈ 𝑉 ∣ ∃𝑒 ∈ 𝐸 ((𝑛 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒) ∨ (𝑛 = 𝑁 ∧ 𝑒 = {𝑛}))}) ↔ (𝑣 ∈ {𝑁} ∨ 𝑣 ∈ {𝑛 ∈ 𝑉 ∣ ∃𝑒 ∈ 𝐸 ((𝑛 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒) ∨ (𝑛 = 𝑁 ∧ 𝑒 = {𝑛}))})) | 
| 38 |  | neeq1 3003 | . . . . . . . . . 10
⊢ (𝑛 = 𝑣 → (𝑛 ≠ 𝑁 ↔ 𝑣 ≠ 𝑁)) | 
| 39 | 38, 31 | 3anbi13d 1440 | . . . . . . . . 9
⊢ (𝑛 = 𝑣 → ((𝑛 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒) ↔ (𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒))) | 
| 40 |  | eqeq1 2741 | . . . . . . . . . 10
⊢ (𝑛 = 𝑣 → (𝑛 = 𝑁 ↔ 𝑣 = 𝑁)) | 
| 41 |  | sneq 4636 | . . . . . . . . . . 11
⊢ (𝑛 = 𝑣 → {𝑛} = {𝑣}) | 
| 42 | 41 | eqeq2d 2748 | . . . . . . . . . 10
⊢ (𝑛 = 𝑣 → (𝑒 = {𝑛} ↔ 𝑒 = {𝑣})) | 
| 43 | 40, 42 | anbi12d 632 | . . . . . . . . 9
⊢ (𝑛 = 𝑣 → ((𝑛 = 𝑁 ∧ 𝑒 = {𝑛}) ↔ (𝑣 = 𝑁 ∧ 𝑒 = {𝑣}))) | 
| 44 | 39, 43 | orbi12d 919 | . . . . . . . 8
⊢ (𝑛 = 𝑣 → (((𝑛 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒) ∨ (𝑛 = 𝑁 ∧ 𝑒 = {𝑛})) ↔ ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ∨ (𝑣 = 𝑁 ∧ 𝑒 = {𝑣})))) | 
| 45 | 44 | rexbidv 3179 | . . . . . . 7
⊢ (𝑛 = 𝑣 → (∃𝑒 ∈ 𝐸 ((𝑛 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒) ∨ (𝑛 = 𝑁 ∧ 𝑒 = {𝑛})) ↔ ∃𝑒 ∈ 𝐸 ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ∨ (𝑣 = 𝑁 ∧ 𝑒 = {𝑣})))) | 
| 46 | 45 | elrab 3692 | . . . . . 6
⊢ (𝑣 ∈ {𝑛 ∈ 𝑉 ∣ ∃𝑒 ∈ 𝐸 ((𝑛 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒) ∨ (𝑛 = 𝑁 ∧ 𝑒 = {𝑛}))} ↔ (𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ∨ (𝑣 = 𝑁 ∧ 𝑒 = {𝑣})))) | 
| 47 | 30, 46 | orbi12i 915 | . . . . 5
⊢ ((𝑣 ∈ {𝑁} ∨ 𝑣 ∈ {𝑛 ∈ 𝑉 ∣ ∃𝑒 ∈ 𝐸 ((𝑛 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒) ∨ (𝑛 = 𝑁 ∧ 𝑒 = {𝑛}))}) ↔ (𝑣 = 𝑁 ∨ (𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ∨ (𝑣 = 𝑁 ∧ 𝑒 = {𝑣}))))) | 
| 48 | 37, 47 | bitri 275 | . . . 4
⊢ (𝑣 ∈ ({𝑁} ∪ {𝑛 ∈ 𝑉 ∣ ∃𝑒 ∈ 𝐸 ((𝑛 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒) ∨ (𝑛 = 𝑁 ∧ 𝑒 = {𝑛}))}) ↔ (𝑣 = 𝑁 ∨ (𝑣 ∈ 𝑉 ∧ ∃𝑒 ∈ 𝐸 ((𝑣 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑣 ∈ 𝑒) ∨ (𝑣 = 𝑁 ∧ 𝑒 = {𝑣}))))) | 
| 49 | 28, 36, 48 | 3bitr4g 314 | . . 3
⊢ (𝑁 ∈ 𝑉 → (𝑣 ∈ ({𝑁} ∪ {𝑛 ∈ 𝑉 ∣ ∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒)}) ↔ 𝑣 ∈ ({𝑁} ∪ {𝑛 ∈ 𝑉 ∣ ∃𝑒 ∈ 𝐸 ((𝑛 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒) ∨ (𝑛 = 𝑁 ∧ 𝑒 = {𝑛}))}))) | 
| 50 | 49 | eqrdv 2735 | . 2
⊢ (𝑁 ∈ 𝑉 → ({𝑁} ∪ {𝑛 ∈ 𝑉 ∣ ∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒)}) = ({𝑁} ∪ {𝑛 ∈ 𝑉 ∣ ∃𝑒 ∈ 𝐸 ((𝑛 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒) ∨ (𝑛 = 𝑁 ∧ 𝑒 = {𝑛}))})) | 
| 51 |  | dfvopnbgr2.v | . . 3
⊢ 𝑉 = (Vtx‘𝐺) | 
| 52 |  | dfvopnbgr2.e | . . 3
⊢ 𝐸 = (Edg‘𝐺) | 
| 53 | 51, 52 | dfclnbgr2 47810 | . 2
⊢ (𝑁 ∈ 𝑉 → (𝐺 ClNeighbVtx 𝑁) = ({𝑁} ∪ {𝑛 ∈ 𝑉 ∣ ∃𝑒 ∈ 𝐸 (𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒)})) | 
| 54 |  | dfvopnbgr2.u | . . . 4
⊢ 𝑈 = {𝑛 ∈ 𝑉 ∣ (𝑛 ∈ (𝐺 NeighbVtx 𝑁) ∨ ∃𝑒 ∈ 𝐸 (𝑁 = 𝑛 ∧ 𝑒 = {𝑁}))} | 
| 55 | 51, 52, 54 | dfvopnbgr2 47839 | . . 3
⊢ (𝑁 ∈ 𝑉 → 𝑈 = {𝑛 ∈ 𝑉 ∣ ∃𝑒 ∈ 𝐸 ((𝑛 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒) ∨ (𝑛 = 𝑁 ∧ 𝑒 = {𝑛}))}) | 
| 56 | 55 | uneq2d 4168 | . 2
⊢ (𝑁 ∈ 𝑉 → ({𝑁} ∪ 𝑈) = ({𝑁} ∪ {𝑛 ∈ 𝑉 ∣ ∃𝑒 ∈ 𝐸 ((𝑛 ≠ 𝑁 ∧ 𝑁 ∈ 𝑒 ∧ 𝑛 ∈ 𝑒) ∨ (𝑛 = 𝑁 ∧ 𝑒 = {𝑛}))})) | 
| 57 | 50, 53, 56 | 3eqtr4d 2787 | 1
⊢ (𝑁 ∈ 𝑉 → (𝐺 ClNeighbVtx 𝑁) = ({𝑁} ∪ 𝑈)) |