| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | ssn0 4404 | . . . . . . . . 9
⊢ ((𝑠 ⊆ (𝐴 × 𝐵) ∧ 𝑠 ≠ ∅) → (𝐴 × 𝐵) ≠ ∅) | 
| 2 |  | xpnz 6179 | . . . . . . . . . . 11
⊢ ((𝐴 ≠ ∅ ∧ 𝐵 ≠ ∅) ↔ (𝐴 × 𝐵) ≠ ∅) | 
| 3 | 2 | biimpri 228 | . . . . . . . . . 10
⊢ ((𝐴 × 𝐵) ≠ ∅ → (𝐴 ≠ ∅ ∧ 𝐵 ≠ ∅)) | 
| 4 | 3 | simprd 495 | . . . . . . . . 9
⊢ ((𝐴 × 𝐵) ≠ ∅ → 𝐵 ≠ ∅) | 
| 5 | 1, 4 | syl 17 | . . . . . . . 8
⊢ ((𝑠 ⊆ (𝐴 × 𝐵) ∧ 𝑠 ≠ ∅) → 𝐵 ≠ ∅) | 
| 6 |  | dmxp 5939 | . . . . . . . . . 10
⊢ (𝐵 ≠ ∅ → dom (𝐴 × 𝐵) = 𝐴) | 
| 7 |  | dmss 5913 | . . . . . . . . . . 11
⊢ (𝑠 ⊆ (𝐴 × 𝐵) → dom 𝑠 ⊆ dom (𝐴 × 𝐵)) | 
| 8 |  | sseq2 4010 | . . . . . . . . . . 11
⊢ (dom
(𝐴 × 𝐵) = 𝐴 → (dom 𝑠 ⊆ dom (𝐴 × 𝐵) ↔ dom 𝑠 ⊆ 𝐴)) | 
| 9 | 7, 8 | imbitrid 244 | . . . . . . . . . 10
⊢ (dom
(𝐴 × 𝐵) = 𝐴 → (𝑠 ⊆ (𝐴 × 𝐵) → dom 𝑠 ⊆ 𝐴)) | 
| 10 | 6, 9 | syl 17 | . . . . . . . . 9
⊢ (𝐵 ≠ ∅ → (𝑠 ⊆ (𝐴 × 𝐵) → dom 𝑠 ⊆ 𝐴)) | 
| 11 | 10 | impcom 407 | . . . . . . . 8
⊢ ((𝑠 ⊆ (𝐴 × 𝐵) ∧ 𝐵 ≠ ∅) → dom 𝑠 ⊆ 𝐴) | 
| 12 | 5, 11 | syldan 591 | . . . . . . 7
⊢ ((𝑠 ⊆ (𝐴 × 𝐵) ∧ 𝑠 ≠ ∅) → dom 𝑠 ⊆ 𝐴) | 
| 13 |  | relxp 5703 | . . . . . . . . . . 11
⊢ Rel
(𝐴 × 𝐵) | 
| 14 |  | relss 5791 | . . . . . . . . . . 11
⊢ (𝑠 ⊆ (𝐴 × 𝐵) → (Rel (𝐴 × 𝐵) → Rel 𝑠)) | 
| 15 | 13, 14 | mpi 20 | . . . . . . . . . 10
⊢ (𝑠 ⊆ (𝐴 × 𝐵) → Rel 𝑠) | 
| 16 |  | reldm0 5938 | . . . . . . . . . 10
⊢ (Rel
𝑠 → (𝑠 = ∅ ↔ dom 𝑠 = ∅)) | 
| 17 | 15, 16 | syl 17 | . . . . . . . . 9
⊢ (𝑠 ⊆ (𝐴 × 𝐵) → (𝑠 = ∅ ↔ dom 𝑠 = ∅)) | 
| 18 | 17 | necon3bid 2985 | . . . . . . . 8
⊢ (𝑠 ⊆ (𝐴 × 𝐵) → (𝑠 ≠ ∅ ↔ dom 𝑠 ≠ ∅)) | 
| 19 | 18 | biimpa 476 | . . . . . . 7
⊢ ((𝑠 ⊆ (𝐴 × 𝐵) ∧ 𝑠 ≠ ∅) → dom 𝑠 ≠ ∅) | 
| 20 | 12, 19 | jca 511 | . . . . . 6
⊢ ((𝑠 ⊆ (𝐴 × 𝐵) ∧ 𝑠 ≠ ∅) → (dom 𝑠 ⊆ 𝐴 ∧ dom 𝑠 ≠ ∅)) | 
| 21 |  | df-fr 5637 | . . . . . . 7
⊢ (𝑅 Fr 𝐴 ↔ ∀𝑣((𝑣 ⊆ 𝐴 ∧ 𝑣 ≠ ∅) → ∃𝑎 ∈ 𝑣 ∀𝑐 ∈ 𝑣 ¬ 𝑐𝑅𝑎)) | 
| 22 |  | vex 3484 | . . . . . . . . 9
⊢ 𝑠 ∈ V | 
| 23 | 22 | dmex 7931 | . . . . . . . 8
⊢ dom 𝑠 ∈ V | 
| 24 |  | sseq1 4009 | . . . . . . . . . 10
⊢ (𝑣 = dom 𝑠 → (𝑣 ⊆ 𝐴 ↔ dom 𝑠 ⊆ 𝐴)) | 
| 25 |  | neeq1 3003 | . . . . . . . . . 10
⊢ (𝑣 = dom 𝑠 → (𝑣 ≠ ∅ ↔ dom 𝑠 ≠ ∅)) | 
| 26 | 24, 25 | anbi12d 632 | . . . . . . . . 9
⊢ (𝑣 = dom 𝑠 → ((𝑣 ⊆ 𝐴 ∧ 𝑣 ≠ ∅) ↔ (dom 𝑠 ⊆ 𝐴 ∧ dom 𝑠 ≠ ∅))) | 
| 27 |  | raleq 3323 | . . . . . . . . . 10
⊢ (𝑣 = dom 𝑠 → (∀𝑐 ∈ 𝑣 ¬ 𝑐𝑅𝑎 ↔ ∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎)) | 
| 28 | 27 | rexeqbi1dv 3339 | . . . . . . . . 9
⊢ (𝑣 = dom 𝑠 → (∃𝑎 ∈ 𝑣 ∀𝑐 ∈ 𝑣 ¬ 𝑐𝑅𝑎 ↔ ∃𝑎 ∈ dom 𝑠∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎)) | 
| 29 | 26, 28 | imbi12d 344 | . . . . . . . 8
⊢ (𝑣 = dom 𝑠 → (((𝑣 ⊆ 𝐴 ∧ 𝑣 ≠ ∅) → ∃𝑎 ∈ 𝑣 ∀𝑐 ∈ 𝑣 ¬ 𝑐𝑅𝑎) ↔ ((dom 𝑠 ⊆ 𝐴 ∧ dom 𝑠 ≠ ∅) → ∃𝑎 ∈ dom 𝑠∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎))) | 
| 30 | 23, 29 | spcv 3605 | . . . . . . 7
⊢
(∀𝑣((𝑣 ⊆ 𝐴 ∧ 𝑣 ≠ ∅) → ∃𝑎 ∈ 𝑣 ∀𝑐 ∈ 𝑣 ¬ 𝑐𝑅𝑎) → ((dom 𝑠 ⊆ 𝐴 ∧ dom 𝑠 ≠ ∅) → ∃𝑎 ∈ dom 𝑠∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎)) | 
| 31 | 21, 30 | sylbi 217 | . . . . . 6
⊢ (𝑅 Fr 𝐴 → ((dom 𝑠 ⊆ 𝐴 ∧ dom 𝑠 ≠ ∅) → ∃𝑎 ∈ dom 𝑠∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎)) | 
| 32 | 20, 31 | syl5 34 | . . . . 5
⊢ (𝑅 Fr 𝐴 → ((𝑠 ⊆ (𝐴 × 𝐵) ∧ 𝑠 ≠ ∅) → ∃𝑎 ∈ dom 𝑠∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎)) | 
| 33 | 32 | adantr 480 | . . . 4
⊢ ((𝑅 Fr 𝐴 ∧ 𝑆 Fr 𝐵) → ((𝑠 ⊆ (𝐴 × 𝐵) ∧ 𝑠 ≠ ∅) → ∃𝑎 ∈ dom 𝑠∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎)) | 
| 34 |  | imassrn 6089 | . . . . . . . . . . . . . . 15
⊢ (𝑠 “ {𝑎}) ⊆ ran 𝑠 | 
| 35 |  | xpeq0 6180 | . . . . . . . . . . . . . . . . . . . 20
⊢ ((𝐴 × 𝐵) = ∅ ↔ (𝐴 = ∅ ∨ 𝐵 = ∅)) | 
| 36 | 35 | biimpri 228 | . . . . . . . . . . . . . . . . . . 19
⊢ ((𝐴 = ∅ ∨ 𝐵 = ∅) → (𝐴 × 𝐵) = ∅) | 
| 37 | 36 | orcs 876 | . . . . . . . . . . . . . . . . . 18
⊢ (𝐴 = ∅ → (𝐴 × 𝐵) = ∅) | 
| 38 |  | sseq2 4010 | . . . . . . . . . . . . . . . . . . 19
⊢ ((𝐴 × 𝐵) = ∅ → (𝑠 ⊆ (𝐴 × 𝐵) ↔ 𝑠 ⊆ ∅)) | 
| 39 |  | ss0 4402 | . . . . . . . . . . . . . . . . . . 19
⊢ (𝑠 ⊆ ∅ → 𝑠 = ∅) | 
| 40 | 38, 39 | biimtrdi 253 | . . . . . . . . . . . . . . . . . 18
⊢ ((𝐴 × 𝐵) = ∅ → (𝑠 ⊆ (𝐴 × 𝐵) → 𝑠 = ∅)) | 
| 41 | 37, 40 | syl 17 | . . . . . . . . . . . . . . . . 17
⊢ (𝐴 = ∅ → (𝑠 ⊆ (𝐴 × 𝐵) → 𝑠 = ∅)) | 
| 42 |  | rneq 5947 | . . . . . . . . . . . . . . . . . 18
⊢ (𝑠 = ∅ → ran 𝑠 = ran ∅) | 
| 43 |  | rn0 5936 | . . . . . . . . . . . . . . . . . . 19
⊢ ran
∅ = ∅ | 
| 44 |  | 0ss 4400 | . . . . . . . . . . . . . . . . . . 19
⊢ ∅
⊆ 𝐵 | 
| 45 | 43, 44 | eqsstri 4030 | . . . . . . . . . . . . . . . . . 18
⊢ ran
∅ ⊆ 𝐵 | 
| 46 | 42, 45 | eqsstrdi 4028 | . . . . . . . . . . . . . . . . 17
⊢ (𝑠 = ∅ → ran 𝑠 ⊆ 𝐵) | 
| 47 | 41, 46 | syl6 35 | . . . . . . . . . . . . . . . 16
⊢ (𝐴 = ∅ → (𝑠 ⊆ (𝐴 × 𝐵) → ran 𝑠 ⊆ 𝐵)) | 
| 48 |  | rnxp 6190 | . . . . . . . . . . . . . . . . 17
⊢ (𝐴 ≠ ∅ → ran (𝐴 × 𝐵) = 𝐵) | 
| 49 |  | rnss 5950 | . . . . . . . . . . . . . . . . . 18
⊢ (𝑠 ⊆ (𝐴 × 𝐵) → ran 𝑠 ⊆ ran (𝐴 × 𝐵)) | 
| 50 |  | sseq2 4010 | . . . . . . . . . . . . . . . . . 18
⊢ (ran
(𝐴 × 𝐵) = 𝐵 → (ran 𝑠 ⊆ ran (𝐴 × 𝐵) ↔ ran 𝑠 ⊆ 𝐵)) | 
| 51 | 49, 50 | imbitrid 244 | . . . . . . . . . . . . . . . . 17
⊢ (ran
(𝐴 × 𝐵) = 𝐵 → (𝑠 ⊆ (𝐴 × 𝐵) → ran 𝑠 ⊆ 𝐵)) | 
| 52 | 48, 51 | syl 17 | . . . . . . . . . . . . . . . 16
⊢ (𝐴 ≠ ∅ → (𝑠 ⊆ (𝐴 × 𝐵) → ran 𝑠 ⊆ 𝐵)) | 
| 53 | 47, 52 | pm2.61ine 3025 | . . . . . . . . . . . . . . 15
⊢ (𝑠 ⊆ (𝐴 × 𝐵) → ran 𝑠 ⊆ 𝐵) | 
| 54 | 34, 53 | sstrid 3995 | . . . . . . . . . . . . . 14
⊢ (𝑠 ⊆ (𝐴 × 𝐵) → (𝑠 “ {𝑎}) ⊆ 𝐵) | 
| 55 |  | vex 3484 | . . . . . . . . . . . . . . . 16
⊢ 𝑎 ∈ V | 
| 56 | 55 | eldm 5911 | . . . . . . . . . . . . . . 15
⊢ (𝑎 ∈ dom 𝑠 ↔ ∃𝑏 𝑎𝑠𝑏) | 
| 57 |  | vex 3484 | . . . . . . . . . . . . . . . . . . 19
⊢ 𝑏 ∈ V | 
| 58 | 55, 57 | elimasn 6108 | . . . . . . . . . . . . . . . . . 18
⊢ (𝑏 ∈ (𝑠 “ {𝑎}) ↔ 〈𝑎, 𝑏〉 ∈ 𝑠) | 
| 59 |  | df-br 5144 | . . . . . . . . . . . . . . . . . 18
⊢ (𝑎𝑠𝑏 ↔ 〈𝑎, 𝑏〉 ∈ 𝑠) | 
| 60 | 58, 59 | bitr4i 278 | . . . . . . . . . . . . . . . . 17
⊢ (𝑏 ∈ (𝑠 “ {𝑎}) ↔ 𝑎𝑠𝑏) | 
| 61 |  | ne0i 4341 | . . . . . . . . . . . . . . . . 17
⊢ (𝑏 ∈ (𝑠 “ {𝑎}) → (𝑠 “ {𝑎}) ≠ ∅) | 
| 62 | 60, 61 | sylbir 235 | . . . . . . . . . . . . . . . 16
⊢ (𝑎𝑠𝑏 → (𝑠 “ {𝑎}) ≠ ∅) | 
| 63 | 62 | exlimiv 1930 | . . . . . . . . . . . . . . 15
⊢
(∃𝑏 𝑎𝑠𝑏 → (𝑠 “ {𝑎}) ≠ ∅) | 
| 64 | 56, 63 | sylbi 217 | . . . . . . . . . . . . . 14
⊢ (𝑎 ∈ dom 𝑠 → (𝑠 “ {𝑎}) ≠ ∅) | 
| 65 |  | df-fr 5637 | . . . . . . . . . . . . . . 15
⊢ (𝑆 Fr 𝐵 ↔ ∀𝑣((𝑣 ⊆ 𝐵 ∧ 𝑣 ≠ ∅) → ∃𝑏 ∈ 𝑣 ∀𝑑 ∈ 𝑣 ¬ 𝑑𝑆𝑏)) | 
| 66 | 22 | imaex 7936 | . . . . . . . . . . . . . . . 16
⊢ (𝑠 “ {𝑎}) ∈ V | 
| 67 |  | sseq1 4009 | . . . . . . . . . . . . . . . . . 18
⊢ (𝑣 = (𝑠 “ {𝑎}) → (𝑣 ⊆ 𝐵 ↔ (𝑠 “ {𝑎}) ⊆ 𝐵)) | 
| 68 |  | neeq1 3003 | . . . . . . . . . . . . . . . . . 18
⊢ (𝑣 = (𝑠 “ {𝑎}) → (𝑣 ≠ ∅ ↔ (𝑠 “ {𝑎}) ≠ ∅)) | 
| 69 | 67, 68 | anbi12d 632 | . . . . . . . . . . . . . . . . 17
⊢ (𝑣 = (𝑠 “ {𝑎}) → ((𝑣 ⊆ 𝐵 ∧ 𝑣 ≠ ∅) ↔ ((𝑠 “ {𝑎}) ⊆ 𝐵 ∧ (𝑠 “ {𝑎}) ≠ ∅))) | 
| 70 |  | raleq 3323 | . . . . . . . . . . . . . . . . . 18
⊢ (𝑣 = (𝑠 “ {𝑎}) → (∀𝑑 ∈ 𝑣 ¬ 𝑑𝑆𝑏 ↔ ∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏)) | 
| 71 | 70 | rexeqbi1dv 3339 | . . . . . . . . . . . . . . . . 17
⊢ (𝑣 = (𝑠 “ {𝑎}) → (∃𝑏 ∈ 𝑣 ∀𝑑 ∈ 𝑣 ¬ 𝑑𝑆𝑏 ↔ ∃𝑏 ∈ (𝑠 “ {𝑎})∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏)) | 
| 72 | 69, 71 | imbi12d 344 | . . . . . . . . . . . . . . . 16
⊢ (𝑣 = (𝑠 “ {𝑎}) → (((𝑣 ⊆ 𝐵 ∧ 𝑣 ≠ ∅) → ∃𝑏 ∈ 𝑣 ∀𝑑 ∈ 𝑣 ¬ 𝑑𝑆𝑏) ↔ (((𝑠 “ {𝑎}) ⊆ 𝐵 ∧ (𝑠 “ {𝑎}) ≠ ∅) → ∃𝑏 ∈ (𝑠 “ {𝑎})∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏))) | 
| 73 | 66, 72 | spcv 3605 | . . . . . . . . . . . . . . 15
⊢
(∀𝑣((𝑣 ⊆ 𝐵 ∧ 𝑣 ≠ ∅) → ∃𝑏 ∈ 𝑣 ∀𝑑 ∈ 𝑣 ¬ 𝑑𝑆𝑏) → (((𝑠 “ {𝑎}) ⊆ 𝐵 ∧ (𝑠 “ {𝑎}) ≠ ∅) → ∃𝑏 ∈ (𝑠 “ {𝑎})∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏)) | 
| 74 | 65, 73 | sylbi 217 | . . . . . . . . . . . . . 14
⊢ (𝑆 Fr 𝐵 → (((𝑠 “ {𝑎}) ⊆ 𝐵 ∧ (𝑠 “ {𝑎}) ≠ ∅) → ∃𝑏 ∈ (𝑠 “ {𝑎})∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏)) | 
| 75 | 54, 64, 74 | syl2ani 607 | . . . . . . . . . . . . 13
⊢ (𝑆 Fr 𝐵 → ((𝑠 ⊆ (𝐴 × 𝐵) ∧ 𝑎 ∈ dom 𝑠) → ∃𝑏 ∈ (𝑠 “ {𝑎})∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏)) | 
| 76 |  | 1stdm 8065 | . . . . . . . . . . . . . . . . . . . . . . . . . . 27
⊢ ((Rel
𝑠 ∧ 𝑤 ∈ 𝑠) → (1st ‘𝑤) ∈ dom 𝑠) | 
| 77 |  | breq1 5146 | . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
⊢ (𝑐 = (1st ‘𝑤) → (𝑐𝑅𝑎 ↔ (1st ‘𝑤)𝑅𝑎)) | 
| 78 | 77 | notbid 318 | . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
⊢ (𝑐 = (1st ‘𝑤) → (¬ 𝑐𝑅𝑎 ↔ ¬ (1st ‘𝑤)𝑅𝑎)) | 
| 79 | 78 | rspccv 3619 | . . . . . . . . . . . . . . . . . . . . . . . . . . 27
⊢
(∀𝑐 ∈
dom 𝑠 ¬ 𝑐𝑅𝑎 → ((1st ‘𝑤) ∈ dom 𝑠 → ¬ (1st ‘𝑤)𝑅𝑎)) | 
| 80 | 76, 79 | syl5 34 | . . . . . . . . . . . . . . . . . . . . . . . . . 26
⊢
(∀𝑐 ∈
dom 𝑠 ¬ 𝑐𝑅𝑎 → ((Rel 𝑠 ∧ 𝑤 ∈ 𝑠) → ¬ (1st ‘𝑤)𝑅𝑎)) | 
| 81 | 80 | expd 415 | . . . . . . . . . . . . . . . . . . . . . . . . 25
⊢
(∀𝑐 ∈
dom 𝑠 ¬ 𝑐𝑅𝑎 → (Rel 𝑠 → (𝑤 ∈ 𝑠 → ¬ (1st ‘𝑤)𝑅𝑎))) | 
| 82 | 81 | impcom 407 | . . . . . . . . . . . . . . . . . . . . . . . 24
⊢ ((Rel
𝑠 ∧ ∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎) → (𝑤 ∈ 𝑠 → ¬ (1st ‘𝑤)𝑅𝑎)) | 
| 83 | 82 | adantr 480 | . . . . . . . . . . . . . . . . . . . . . . 23
⊢ (((Rel
𝑠 ∧ ∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎) ∧ ∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏) → (𝑤 ∈ 𝑠 → ¬ (1st ‘𝑤)𝑅𝑎)) | 
| 84 |  | elrel 5808 | . . . . . . . . . . . . . . . . . . . . . . . . . . 27
⊢ ((Rel
𝑠 ∧ 𝑤 ∈ 𝑠) → ∃𝑡∃𝑢 𝑤 = 〈𝑡, 𝑢〉) | 
| 85 | 84 | ex 412 | . . . . . . . . . . . . . . . . . . . . . . . . . 26
⊢ (Rel
𝑠 → (𝑤 ∈ 𝑠 → ∃𝑡∃𝑢 𝑤 = 〈𝑡, 𝑢〉)) | 
| 86 | 85 | adantr 480 | . . . . . . . . . . . . . . . . . . . . . . . . 25
⊢ ((Rel
𝑠 ∧ ∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏) → (𝑤 ∈ 𝑠 → ∃𝑡∃𝑢 𝑤 = 〈𝑡, 𝑢〉)) | 
| 87 |  | vex 3484 | . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
33
⊢ 𝑢 ∈ V | 
| 88 | 55, 87 | elimasn 6108 | . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
32
⊢ (𝑢 ∈ (𝑠 “ {𝑎}) ↔ 〈𝑎, 𝑢〉 ∈ 𝑠) | 
| 89 |  | breq1 5146 | . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
34
⊢ (𝑑 = 𝑢 → (𝑑𝑆𝑏 ↔ 𝑢𝑆𝑏)) | 
| 90 | 89 | notbid 318 | . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
33
⊢ (𝑑 = 𝑢 → (¬ 𝑑𝑆𝑏 ↔ ¬ 𝑢𝑆𝑏)) | 
| 91 | 90 | rspccv 3619 | . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
32
⊢
(∀𝑑 ∈
(𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏 → (𝑢 ∈ (𝑠 “ {𝑎}) → ¬ 𝑢𝑆𝑏)) | 
| 92 | 88, 91 | biimtrrid 243 | . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
31
⊢
(∀𝑑 ∈
(𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏 → (〈𝑎, 𝑢〉 ∈ 𝑠 → ¬ 𝑢𝑆𝑏)) | 
| 93 | 92 | adantl 481 | . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30
⊢ ((Rel
𝑠 ∧ ∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏) → (〈𝑎, 𝑢〉 ∈ 𝑠 → ¬ 𝑢𝑆𝑏)) | 
| 94 |  | opeq1 4873 | . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
32
⊢ (𝑡 = 𝑎 → 〈𝑡, 𝑢〉 = 〈𝑎, 𝑢〉) | 
| 95 | 94 | eleq1d 2826 | . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
31
⊢ (𝑡 = 𝑎 → (〈𝑡, 𝑢〉 ∈ 𝑠 ↔ 〈𝑎, 𝑢〉 ∈ 𝑠)) | 
| 96 | 95 | imbi1d 341 | . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30
⊢ (𝑡 = 𝑎 → ((〈𝑡, 𝑢〉 ∈ 𝑠 → ¬ 𝑢𝑆𝑏) ↔ (〈𝑎, 𝑢〉 ∈ 𝑠 → ¬ 𝑢𝑆𝑏))) | 
| 97 | 93, 96 | imbitrrid 246 | . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
⊢ (𝑡 = 𝑎 → ((Rel 𝑠 ∧ ∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏) → (〈𝑡, 𝑢〉 ∈ 𝑠 → ¬ 𝑢𝑆𝑏))) | 
| 98 | 97 | com3l 89 | . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
⊢ ((Rel
𝑠 ∧ ∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏) → (〈𝑡, 𝑢〉 ∈ 𝑠 → (𝑡 = 𝑎 → ¬ 𝑢𝑆𝑏))) | 
| 99 |  | eleq1 2829 | . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
⊢ (𝑤 = 〈𝑡, 𝑢〉 → (𝑤 ∈ 𝑠 ↔ 〈𝑡, 𝑢〉 ∈ 𝑠)) | 
| 100 |  | vex 3484 | . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
32
⊢ 𝑡 ∈ V | 
| 101 | 100, 87 | op1std 8024 | . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
31
⊢ (𝑤 = 〈𝑡, 𝑢〉 → (1st ‘𝑤) = 𝑡) | 
| 102 | 101 | eqeq1d 2739 | . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30
⊢ (𝑤 = 〈𝑡, 𝑢〉 → ((1st ‘𝑤) = 𝑎 ↔ 𝑡 = 𝑎)) | 
| 103 | 100, 87 | op2ndd 8025 | . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
32
⊢ (𝑤 = 〈𝑡, 𝑢〉 → (2nd ‘𝑤) = 𝑢) | 
| 104 | 103 | breq1d 5153 | . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
31
⊢ (𝑤 = 〈𝑡, 𝑢〉 → ((2nd ‘𝑤)𝑆𝑏 ↔ 𝑢𝑆𝑏)) | 
| 105 | 104 | notbid 318 | . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30
⊢ (𝑤 = 〈𝑡, 𝑢〉 → (¬ (2nd
‘𝑤)𝑆𝑏 ↔ ¬ 𝑢𝑆𝑏)) | 
| 106 | 102, 105 | imbi12d 344 | . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
⊢ (𝑤 = 〈𝑡, 𝑢〉 → (((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏) ↔ (𝑡 = 𝑎 → ¬ 𝑢𝑆𝑏))) | 
| 107 | 99, 106 | imbi12d 344 | . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
⊢ (𝑤 = 〈𝑡, 𝑢〉 → ((𝑤 ∈ 𝑠 → ((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏)) ↔ (〈𝑡, 𝑢〉 ∈ 𝑠 → (𝑡 = 𝑎 → ¬ 𝑢𝑆𝑏)))) | 
| 108 | 98, 107 | imbitrrid 246 | . . . . . . . . . . . . . . . . . . . . . . . . . . 27
⊢ (𝑤 = 〈𝑡, 𝑢〉 → ((Rel 𝑠 ∧ ∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏) → (𝑤 ∈ 𝑠 → ((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏)))) | 
| 109 | 108 | exlimivv 1932 | . . . . . . . . . . . . . . . . . . . . . . . . . 26
⊢
(∃𝑡∃𝑢 𝑤 = 〈𝑡, 𝑢〉 → ((Rel 𝑠 ∧ ∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏) → (𝑤 ∈ 𝑠 → ((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏)))) | 
| 110 | 109 | com3l 89 | . . . . . . . . . . . . . . . . . . . . . . . . 25
⊢ ((Rel
𝑠 ∧ ∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏) → (𝑤 ∈ 𝑠 → (∃𝑡∃𝑢 𝑤 = 〈𝑡, 𝑢〉 → ((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏)))) | 
| 111 | 86, 110 | mpdd 43 | . . . . . . . . . . . . . . . . . . . . . . . 24
⊢ ((Rel
𝑠 ∧ ∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏) → (𝑤 ∈ 𝑠 → ((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏))) | 
| 112 | 111 | adantlr 715 | . . . . . . . . . . . . . . . . . . . . . . 23
⊢ (((Rel
𝑠 ∧ ∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎) ∧ ∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏) → (𝑤 ∈ 𝑠 → ((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏))) | 
| 113 | 83, 112 | jcad 512 | . . . . . . . . . . . . . . . . . . . . . 22
⊢ (((Rel
𝑠 ∧ ∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎) ∧ ∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏) → (𝑤 ∈ 𝑠 → (¬ (1st ‘𝑤)𝑅𝑎 ∧ ((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏)))) | 
| 114 | 113 | ralrimiv 3145 | . . . . . . . . . . . . . . . . . . . . 21
⊢ (((Rel
𝑠 ∧ ∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎) ∧ ∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏) → ∀𝑤 ∈ 𝑠 (¬ (1st ‘𝑤)𝑅𝑎 ∧ ((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏))) | 
| 115 | 114 | ex 412 | . . . . . . . . . . . . . . . . . . . 20
⊢ ((Rel
𝑠 ∧ ∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎) → (∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏 → ∀𝑤 ∈ 𝑠 (¬ (1st ‘𝑤)𝑅𝑎 ∧ ((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏)))) | 
| 116 | 15, 115 | sylan 580 | . . . . . . . . . . . . . . . . . . 19
⊢ ((𝑠 ⊆ (𝐴 × 𝐵) ∧ ∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎) → (∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏 → ∀𝑤 ∈ 𝑠 (¬ (1st ‘𝑤)𝑅𝑎 ∧ ((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏)))) | 
| 117 |  | olc 869 | . . . . . . . . . . . . . . . . . . . 20
⊢ ((¬
(1st ‘𝑤)𝑅𝑎 ∧ ((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏)) → (¬ (𝑤 ∈ (𝐴 × 𝐵) ∧ 〈𝑎, 𝑏〉 ∈ (𝐴 × 𝐵)) ∨ (¬ (1st ‘𝑤)𝑅𝑎 ∧ ((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏)))) | 
| 118 | 117 | ralimi 3083 | . . . . . . . . . . . . . . . . . . 19
⊢
(∀𝑤 ∈
𝑠 (¬ (1st
‘𝑤)𝑅𝑎 ∧ ((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏)) → ∀𝑤 ∈ 𝑠 (¬ (𝑤 ∈ (𝐴 × 𝐵) ∧ 〈𝑎, 𝑏〉 ∈ (𝐴 × 𝐵)) ∨ (¬ (1st ‘𝑤)𝑅𝑎 ∧ ((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏)))) | 
| 119 | 116, 118 | syl6 35 | . . . . . . . . . . . . . . . . . 18
⊢ ((𝑠 ⊆ (𝐴 × 𝐵) ∧ ∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎) → (∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏 → ∀𝑤 ∈ 𝑠 (¬ (𝑤 ∈ (𝐴 × 𝐵) ∧ 〈𝑎, 𝑏〉 ∈ (𝐴 × 𝐵)) ∨ (¬ (1st ‘𝑤)𝑅𝑎 ∧ ((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏))))) | 
| 120 |  | ianor 984 | . . . . . . . . . . . . . . . . . . . . 21
⊢ (¬
((𝑤 ∈ (𝐴 × 𝐵) ∧ 〈𝑎, 𝑏〉 ∈ (𝐴 × 𝐵)) ∧ ((1st ‘𝑤)𝑅𝑎 ∨ ((1st ‘𝑤) = 𝑎 ∧ (2nd ‘𝑤)𝑆𝑏))) ↔ (¬ (𝑤 ∈ (𝐴 × 𝐵) ∧ 〈𝑎, 𝑏〉 ∈ (𝐴 × 𝐵)) ∨ ¬ ((1st ‘𝑤)𝑅𝑎 ∨ ((1st ‘𝑤) = 𝑎 ∧ (2nd ‘𝑤)𝑆𝑏)))) | 
| 121 |  | vex 3484 | . . . . . . . . . . . . . . . . . . . . . 22
⊢ 𝑤 ∈ V | 
| 122 |  | opex 5469 | . . . . . . . . . . . . . . . . . . . . . 22
⊢
〈𝑎, 𝑏〉 ∈ V | 
| 123 |  | eleq1 2829 | . . . . . . . . . . . . . . . . . . . . . . . 24
⊢ (𝑥 = 𝑤 → (𝑥 ∈ (𝐴 × 𝐵) ↔ 𝑤 ∈ (𝐴 × 𝐵))) | 
| 124 | 123 | anbi1d 631 | . . . . . . . . . . . . . . . . . . . . . . 23
⊢ (𝑥 = 𝑤 → ((𝑥 ∈ (𝐴 × 𝐵) ∧ 𝑦 ∈ (𝐴 × 𝐵)) ↔ (𝑤 ∈ (𝐴 × 𝐵) ∧ 𝑦 ∈ (𝐴 × 𝐵)))) | 
| 125 |  | fveq2 6906 | . . . . . . . . . . . . . . . . . . . . . . . . 25
⊢ (𝑥 = 𝑤 → (1st ‘𝑥) = (1st ‘𝑤)) | 
| 126 | 125 | breq1d 5153 | . . . . . . . . . . . . . . . . . . . . . . . 24
⊢ (𝑥 = 𝑤 → ((1st ‘𝑥)𝑅(1st ‘𝑦) ↔ (1st ‘𝑤)𝑅(1st ‘𝑦))) | 
| 127 | 125 | eqeq1d 2739 | . . . . . . . . . . . . . . . . . . . . . . . . 25
⊢ (𝑥 = 𝑤 → ((1st ‘𝑥) = (1st ‘𝑦) ↔ (1st
‘𝑤) = (1st
‘𝑦))) | 
| 128 |  | fveq2 6906 | . . . . . . . . . . . . . . . . . . . . . . . . . 26
⊢ (𝑥 = 𝑤 → (2nd ‘𝑥) = (2nd ‘𝑤)) | 
| 129 | 128 | breq1d 5153 | . . . . . . . . . . . . . . . . . . . . . . . . 25
⊢ (𝑥 = 𝑤 → ((2nd ‘𝑥)𝑆(2nd ‘𝑦) ↔ (2nd ‘𝑤)𝑆(2nd ‘𝑦))) | 
| 130 | 127, 129 | anbi12d 632 | . . . . . . . . . . . . . . . . . . . . . . . 24
⊢ (𝑥 = 𝑤 → (((1st ‘𝑥) = (1st ‘𝑦) ∧ (2nd
‘𝑥)𝑆(2nd ‘𝑦)) ↔ ((1st ‘𝑤) = (1st ‘𝑦) ∧ (2nd
‘𝑤)𝑆(2nd ‘𝑦)))) | 
| 131 | 126, 130 | orbi12d 919 | . . . . . . . . . . . . . . . . . . . . . . 23
⊢ (𝑥 = 𝑤 → (((1st ‘𝑥)𝑅(1st ‘𝑦) ∨ ((1st ‘𝑥) = (1st ‘𝑦) ∧ (2nd
‘𝑥)𝑆(2nd ‘𝑦))) ↔ ((1st ‘𝑤)𝑅(1st ‘𝑦) ∨ ((1st ‘𝑤) = (1st ‘𝑦) ∧ (2nd
‘𝑤)𝑆(2nd ‘𝑦))))) | 
| 132 | 124, 131 | anbi12d 632 | . . . . . . . . . . . . . . . . . . . . . 22
⊢ (𝑥 = 𝑤 → (((𝑥 ∈ (𝐴 × 𝐵) ∧ 𝑦 ∈ (𝐴 × 𝐵)) ∧ ((1st ‘𝑥)𝑅(1st ‘𝑦) ∨ ((1st ‘𝑥) = (1st ‘𝑦) ∧ (2nd
‘𝑥)𝑆(2nd ‘𝑦)))) ↔ ((𝑤 ∈ (𝐴 × 𝐵) ∧ 𝑦 ∈ (𝐴 × 𝐵)) ∧ ((1st ‘𝑤)𝑅(1st ‘𝑦) ∨ ((1st ‘𝑤) = (1st ‘𝑦) ∧ (2nd
‘𝑤)𝑆(2nd ‘𝑦)))))) | 
| 133 |  | eleq1 2829 | . . . . . . . . . . . . . . . . . . . . . . . 24
⊢ (𝑦 = 〈𝑎, 𝑏〉 → (𝑦 ∈ (𝐴 × 𝐵) ↔ 〈𝑎, 𝑏〉 ∈ (𝐴 × 𝐵))) | 
| 134 | 133 | anbi2d 630 | . . . . . . . . . . . . . . . . . . . . . . 23
⊢ (𝑦 = 〈𝑎, 𝑏〉 → ((𝑤 ∈ (𝐴 × 𝐵) ∧ 𝑦 ∈ (𝐴 × 𝐵)) ↔ (𝑤 ∈ (𝐴 × 𝐵) ∧ 〈𝑎, 𝑏〉 ∈ (𝐴 × 𝐵)))) | 
| 135 | 55, 57 | op1std 8024 | . . . . . . . . . . . . . . . . . . . . . . . . 25
⊢ (𝑦 = 〈𝑎, 𝑏〉 → (1st ‘𝑦) = 𝑎) | 
| 136 | 135 | breq2d 5155 | . . . . . . . . . . . . . . . . . . . . . . . 24
⊢ (𝑦 = 〈𝑎, 𝑏〉 → ((1st ‘𝑤)𝑅(1st ‘𝑦) ↔ (1st ‘𝑤)𝑅𝑎)) | 
| 137 | 135 | eqeq2d 2748 | . . . . . . . . . . . . . . . . . . . . . . . . 25
⊢ (𝑦 = 〈𝑎, 𝑏〉 → ((1st ‘𝑤) = (1st ‘𝑦) ↔ (1st
‘𝑤) = 𝑎)) | 
| 138 | 55, 57 | op2ndd 8025 | . . . . . . . . . . . . . . . . . . . . . . . . . 26
⊢ (𝑦 = 〈𝑎, 𝑏〉 → (2nd ‘𝑦) = 𝑏) | 
| 139 | 138 | breq2d 5155 | . . . . . . . . . . . . . . . . . . . . . . . . 25
⊢ (𝑦 = 〈𝑎, 𝑏〉 → ((2nd ‘𝑤)𝑆(2nd ‘𝑦) ↔ (2nd ‘𝑤)𝑆𝑏)) | 
| 140 | 137, 139 | anbi12d 632 | . . . . . . . . . . . . . . . . . . . . . . . 24
⊢ (𝑦 = 〈𝑎, 𝑏〉 → (((1st ‘𝑤) = (1st ‘𝑦) ∧ (2nd
‘𝑤)𝑆(2nd ‘𝑦)) ↔ ((1st ‘𝑤) = 𝑎 ∧ (2nd ‘𝑤)𝑆𝑏))) | 
| 141 | 136, 140 | orbi12d 919 | . . . . . . . . . . . . . . . . . . . . . . 23
⊢ (𝑦 = 〈𝑎, 𝑏〉 → (((1st ‘𝑤)𝑅(1st ‘𝑦) ∨ ((1st ‘𝑤) = (1st ‘𝑦) ∧ (2nd
‘𝑤)𝑆(2nd ‘𝑦))) ↔ ((1st ‘𝑤)𝑅𝑎 ∨ ((1st ‘𝑤) = 𝑎 ∧ (2nd ‘𝑤)𝑆𝑏)))) | 
| 142 | 134, 141 | anbi12d 632 | . . . . . . . . . . . . . . . . . . . . . 22
⊢ (𝑦 = 〈𝑎, 𝑏〉 → (((𝑤 ∈ (𝐴 × 𝐵) ∧ 𝑦 ∈ (𝐴 × 𝐵)) ∧ ((1st ‘𝑤)𝑅(1st ‘𝑦) ∨ ((1st ‘𝑤) = (1st ‘𝑦) ∧ (2nd
‘𝑤)𝑆(2nd ‘𝑦)))) ↔ ((𝑤 ∈ (𝐴 × 𝐵) ∧ 〈𝑎, 𝑏〉 ∈ (𝐴 × 𝐵)) ∧ ((1st ‘𝑤)𝑅𝑎 ∨ ((1st ‘𝑤) = 𝑎 ∧ (2nd ‘𝑤)𝑆𝑏))))) | 
| 143 |  | frxp.1 | . . . . . . . . . . . . . . . . . . . . . 22
⊢ 𝑇 = {〈𝑥, 𝑦〉 ∣ ((𝑥 ∈ (𝐴 × 𝐵) ∧ 𝑦 ∈ (𝐴 × 𝐵)) ∧ ((1st ‘𝑥)𝑅(1st ‘𝑦) ∨ ((1st ‘𝑥) = (1st ‘𝑦) ∧ (2nd
‘𝑥)𝑆(2nd ‘𝑦))))} | 
| 144 | 121, 122,
132, 142, 143 | brab 5548 | . . . . . . . . . . . . . . . . . . . . 21
⊢ (𝑤𝑇〈𝑎, 𝑏〉 ↔ ((𝑤 ∈ (𝐴 × 𝐵) ∧ 〈𝑎, 𝑏〉 ∈ (𝐴 × 𝐵)) ∧ ((1st ‘𝑤)𝑅𝑎 ∨ ((1st ‘𝑤) = 𝑎 ∧ (2nd ‘𝑤)𝑆𝑏)))) | 
| 145 | 120, 144 | xchnxbir 333 | . . . . . . . . . . . . . . . . . . . 20
⊢ (¬
𝑤𝑇〈𝑎, 𝑏〉 ↔ (¬ (𝑤 ∈ (𝐴 × 𝐵) ∧ 〈𝑎, 𝑏〉 ∈ (𝐴 × 𝐵)) ∨ ¬ ((1st ‘𝑤)𝑅𝑎 ∨ ((1st ‘𝑤) = 𝑎 ∧ (2nd ‘𝑤)𝑆𝑏)))) | 
| 146 |  | ioran 986 | . . . . . . . . . . . . . . . . . . . . . 22
⊢ (¬
((1st ‘𝑤)𝑅𝑎 ∨ ((1st ‘𝑤) = 𝑎 ∧ (2nd ‘𝑤)𝑆𝑏)) ↔ (¬ (1st ‘𝑤)𝑅𝑎 ∧ ¬ ((1st ‘𝑤) = 𝑎 ∧ (2nd ‘𝑤)𝑆𝑏))) | 
| 147 |  | ianor 984 | . . . . . . . . . . . . . . . . . . . . . . . 24
⊢ (¬
((1st ‘𝑤)
= 𝑎 ∧ (2nd
‘𝑤)𝑆𝑏) ↔ (¬ (1st ‘𝑤) = 𝑎 ∨ ¬ (2nd ‘𝑤)𝑆𝑏)) | 
| 148 |  | pm4.62 857 | . . . . . . . . . . . . . . . . . . . . . . . 24
⊢
(((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏) ↔ (¬ (1st ‘𝑤) = 𝑎 ∨ ¬ (2nd ‘𝑤)𝑆𝑏)) | 
| 149 | 147, 148 | bitr4i 278 | . . . . . . . . . . . . . . . . . . . . . . 23
⊢ (¬
((1st ‘𝑤)
= 𝑎 ∧ (2nd
‘𝑤)𝑆𝑏) ↔ ((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏)) | 
| 150 | 149 | anbi2i 623 | . . . . . . . . . . . . . . . . . . . . . 22
⊢ ((¬
(1st ‘𝑤)𝑅𝑎 ∧ ¬ ((1st ‘𝑤) = 𝑎 ∧ (2nd ‘𝑤)𝑆𝑏)) ↔ (¬ (1st ‘𝑤)𝑅𝑎 ∧ ((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏))) | 
| 151 | 146, 150 | bitri 275 | . . . . . . . . . . . . . . . . . . . . 21
⊢ (¬
((1st ‘𝑤)𝑅𝑎 ∨ ((1st ‘𝑤) = 𝑎 ∧ (2nd ‘𝑤)𝑆𝑏)) ↔ (¬ (1st ‘𝑤)𝑅𝑎 ∧ ((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏))) | 
| 152 | 151 | orbi2i 913 | . . . . . . . . . . . . . . . . . . . 20
⊢ ((¬
(𝑤 ∈ (𝐴 × 𝐵) ∧ 〈𝑎, 𝑏〉 ∈ (𝐴 × 𝐵)) ∨ ¬ ((1st ‘𝑤)𝑅𝑎 ∨ ((1st ‘𝑤) = 𝑎 ∧ (2nd ‘𝑤)𝑆𝑏))) ↔ (¬ (𝑤 ∈ (𝐴 × 𝐵) ∧ 〈𝑎, 𝑏〉 ∈ (𝐴 × 𝐵)) ∨ (¬ (1st ‘𝑤)𝑅𝑎 ∧ ((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏)))) | 
| 153 | 145, 152 | bitri 275 | . . . . . . . . . . . . . . . . . . 19
⊢ (¬
𝑤𝑇〈𝑎, 𝑏〉 ↔ (¬ (𝑤 ∈ (𝐴 × 𝐵) ∧ 〈𝑎, 𝑏〉 ∈ (𝐴 × 𝐵)) ∨ (¬ (1st ‘𝑤)𝑅𝑎 ∧ ((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏)))) | 
| 154 | 153 | ralbii 3093 | . . . . . . . . . . . . . . . . . 18
⊢
(∀𝑤 ∈
𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉 ↔ ∀𝑤 ∈ 𝑠 (¬ (𝑤 ∈ (𝐴 × 𝐵) ∧ 〈𝑎, 𝑏〉 ∈ (𝐴 × 𝐵)) ∨ (¬ (1st ‘𝑤)𝑅𝑎 ∧ ((1st ‘𝑤) = 𝑎 → ¬ (2nd ‘𝑤)𝑆𝑏)))) | 
| 155 | 119, 154 | imbitrrdi 252 | . . . . . . . . . . . . . . . . 17
⊢ ((𝑠 ⊆ (𝐴 × 𝐵) ∧ ∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎) → (∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏 → ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉)) | 
| 156 | 155 | reximdv 3170 | . . . . . . . . . . . . . . . 16
⊢ ((𝑠 ⊆ (𝐴 × 𝐵) ∧ ∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎) → (∃𝑏 ∈ (𝑠 “ {𝑎})∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏 → ∃𝑏 ∈ (𝑠 “ {𝑎})∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉)) | 
| 157 | 156 | ex 412 | . . . . . . . . . . . . . . 15
⊢ (𝑠 ⊆ (𝐴 × 𝐵) → (∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎 → (∃𝑏 ∈ (𝑠 “ {𝑎})∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏 → ∃𝑏 ∈ (𝑠 “ {𝑎})∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉))) | 
| 158 | 157 | com23 86 | . . . . . . . . . . . . . 14
⊢ (𝑠 ⊆ (𝐴 × 𝐵) → (∃𝑏 ∈ (𝑠 “ {𝑎})∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏 → (∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎 → ∃𝑏 ∈ (𝑠 “ {𝑎})∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉))) | 
| 159 | 158 | adantr 480 | . . . . . . . . . . . . 13
⊢ ((𝑠 ⊆ (𝐴 × 𝐵) ∧ 𝑎 ∈ dom 𝑠) → (∃𝑏 ∈ (𝑠 “ {𝑎})∀𝑑 ∈ (𝑠 “ {𝑎}) ¬ 𝑑𝑆𝑏 → (∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎 → ∃𝑏 ∈ (𝑠 “ {𝑎})∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉))) | 
| 160 | 75, 159 | sylcom 30 | . . . . . . . . . . . 12
⊢ (𝑆 Fr 𝐵 → ((𝑠 ⊆ (𝐴 × 𝐵) ∧ 𝑎 ∈ dom 𝑠) → (∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎 → ∃𝑏 ∈ (𝑠 “ {𝑎})∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉))) | 
| 161 | 160 | impl 455 | . . . . . . . . . . 11
⊢ (((𝑆 Fr 𝐵 ∧ 𝑠 ⊆ (𝐴 × 𝐵)) ∧ 𝑎 ∈ dom 𝑠) → (∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎 → ∃𝑏 ∈ (𝑠 “ {𝑎})∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉)) | 
| 162 | 161 | expimpd 453 | . . . . . . . . . 10
⊢ ((𝑆 Fr 𝐵 ∧ 𝑠 ⊆ (𝐴 × 𝐵)) → ((𝑎 ∈ dom 𝑠 ∧ ∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎) → ∃𝑏 ∈ (𝑠 “ {𝑎})∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉)) | 
| 163 | 162 | 3adant3 1133 | . . . . . . . . 9
⊢ ((𝑆 Fr 𝐵 ∧ 𝑠 ⊆ (𝐴 × 𝐵) ∧ 𝑠 ≠ ∅) → ((𝑎 ∈ dom 𝑠 ∧ ∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎) → ∃𝑏 ∈ (𝑠 “ {𝑎})∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉)) | 
| 164 |  | resss 6019 | . . . . . . . . . 10
⊢ (𝑠 ↾ {𝑎}) ⊆ 𝑠 | 
| 165 |  | df-rex 3071 | . . . . . . . . . . . . 13
⊢
(∃𝑏 ∈
(𝑠 “ {𝑎})∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉 ↔ ∃𝑏(𝑏 ∈ (𝑠 “ {𝑎}) ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉)) | 
| 166 |  | eqid 2737 | . . . . . . . . . . . . . . . 16
⊢
〈𝑎, 𝑏〉 = 〈𝑎, 𝑏〉 | 
| 167 |  | eqeq1 2741 | . . . . . . . . . . . . . . . . . 18
⊢ (𝑧 = 〈𝑎, 𝑏〉 → (𝑧 = 〈𝑎, 𝑏〉 ↔ 〈𝑎, 𝑏〉 = 〈𝑎, 𝑏〉)) | 
| 168 |  | breq2 5147 | . . . . . . . . . . . . . . . . . . . . 21
⊢ (𝑧 = 〈𝑎, 𝑏〉 → (𝑤𝑇𝑧 ↔ 𝑤𝑇〈𝑎, 𝑏〉)) | 
| 169 | 168 | notbid 318 | . . . . . . . . . . . . . . . . . . . 20
⊢ (𝑧 = 〈𝑎, 𝑏〉 → (¬ 𝑤𝑇𝑧 ↔ ¬ 𝑤𝑇〈𝑎, 𝑏〉)) | 
| 170 | 169 | ralbidv 3178 | . . . . . . . . . . . . . . . . . . 19
⊢ (𝑧 = 〈𝑎, 𝑏〉 → (∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧 ↔ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉)) | 
| 171 | 170 | anbi2d 630 | . . . . . . . . . . . . . . . . . 18
⊢ (𝑧 = 〈𝑎, 𝑏〉 → ((〈𝑎, 𝑏〉 ∈ 𝑠 ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧) ↔ (〈𝑎, 𝑏〉 ∈ 𝑠 ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉))) | 
| 172 | 167, 171 | anbi12d 632 | . . . . . . . . . . . . . . . . 17
⊢ (𝑧 = 〈𝑎, 𝑏〉 → ((𝑧 = 〈𝑎, 𝑏〉 ∧ (〈𝑎, 𝑏〉 ∈ 𝑠 ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧)) ↔ (〈𝑎, 𝑏〉 = 〈𝑎, 𝑏〉 ∧ (〈𝑎, 𝑏〉 ∈ 𝑠 ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉)))) | 
| 173 | 122, 172 | spcev 3606 | . . . . . . . . . . . . . . . 16
⊢
((〈𝑎, 𝑏〉 = 〈𝑎, 𝑏〉 ∧ (〈𝑎, 𝑏〉 ∈ 𝑠 ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉)) → ∃𝑧(𝑧 = 〈𝑎, 𝑏〉 ∧ (〈𝑎, 𝑏〉 ∈ 𝑠 ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧))) | 
| 174 | 166, 173 | mpan 690 | . . . . . . . . . . . . . . 15
⊢
((〈𝑎, 𝑏〉 ∈ 𝑠 ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉) → ∃𝑧(𝑧 = 〈𝑎, 𝑏〉 ∧ (〈𝑎, 𝑏〉 ∈ 𝑠 ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧))) | 
| 175 | 58, 174 | sylanb 581 | . . . . . . . . . . . . . 14
⊢ ((𝑏 ∈ (𝑠 “ {𝑎}) ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉) → ∃𝑧(𝑧 = 〈𝑎, 𝑏〉 ∧ (〈𝑎, 𝑏〉 ∈ 𝑠 ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧))) | 
| 176 | 175 | eximi 1835 | . . . . . . . . . . . . 13
⊢
(∃𝑏(𝑏 ∈ (𝑠 “ {𝑎}) ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉) → ∃𝑏∃𝑧(𝑧 = 〈𝑎, 𝑏〉 ∧ (〈𝑎, 𝑏〉 ∈ 𝑠 ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧))) | 
| 177 | 165, 176 | sylbi 217 | . . . . . . . . . . . 12
⊢
(∃𝑏 ∈
(𝑠 “ {𝑎})∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉 → ∃𝑏∃𝑧(𝑧 = 〈𝑎, 𝑏〉 ∧ (〈𝑎, 𝑏〉 ∈ 𝑠 ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧))) | 
| 178 |  | excom 2162 | . . . . . . . . . . . 12
⊢
(∃𝑏∃𝑧(𝑧 = 〈𝑎, 𝑏〉 ∧ (〈𝑎, 𝑏〉 ∈ 𝑠 ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧)) ↔ ∃𝑧∃𝑏(𝑧 = 〈𝑎, 𝑏〉 ∧ (〈𝑎, 𝑏〉 ∈ 𝑠 ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧))) | 
| 179 | 177, 178 | sylib 218 | . . . . . . . . . . 11
⊢
(∃𝑏 ∈
(𝑠 “ {𝑎})∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉 → ∃𝑧∃𝑏(𝑧 = 〈𝑎, 𝑏〉 ∧ (〈𝑎, 𝑏〉 ∈ 𝑠 ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧))) | 
| 180 |  | df-rex 3071 | . . . . . . . . . . . 12
⊢
(∃𝑧 ∈
(𝑠 ↾ {𝑎})∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧 ↔ ∃𝑧(𝑧 ∈ (𝑠 ↾ {𝑎}) ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧)) | 
| 181 | 55 | elsnres 6039 | . . . . . . . . . . . . . . 15
⊢ (𝑧 ∈ (𝑠 ↾ {𝑎}) ↔ ∃𝑏(𝑧 = 〈𝑎, 𝑏〉 ∧ 〈𝑎, 𝑏〉 ∈ 𝑠)) | 
| 182 | 181 | anbi1i 624 | . . . . . . . . . . . . . 14
⊢ ((𝑧 ∈ (𝑠 ↾ {𝑎}) ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧) ↔ (∃𝑏(𝑧 = 〈𝑎, 𝑏〉 ∧ 〈𝑎, 𝑏〉 ∈ 𝑠) ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧)) | 
| 183 |  | 19.41v 1949 | . . . . . . . . . . . . . 14
⊢
(∃𝑏((𝑧 = 〈𝑎, 𝑏〉 ∧ 〈𝑎, 𝑏〉 ∈ 𝑠) ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧) ↔ (∃𝑏(𝑧 = 〈𝑎, 𝑏〉 ∧ 〈𝑎, 𝑏〉 ∈ 𝑠) ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧)) | 
| 184 |  | anass 468 | . . . . . . . . . . . . . . 15
⊢ (((𝑧 = 〈𝑎, 𝑏〉 ∧ 〈𝑎, 𝑏〉 ∈ 𝑠) ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧) ↔ (𝑧 = 〈𝑎, 𝑏〉 ∧ (〈𝑎, 𝑏〉 ∈ 𝑠 ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧))) | 
| 185 | 184 | exbii 1848 | . . . . . . . . . . . . . 14
⊢
(∃𝑏((𝑧 = 〈𝑎, 𝑏〉 ∧ 〈𝑎, 𝑏〉 ∈ 𝑠) ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧) ↔ ∃𝑏(𝑧 = 〈𝑎, 𝑏〉 ∧ (〈𝑎, 𝑏〉 ∈ 𝑠 ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧))) | 
| 186 | 182, 183,
185 | 3bitr2i 299 | . . . . . . . . . . . . 13
⊢ ((𝑧 ∈ (𝑠 ↾ {𝑎}) ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧) ↔ ∃𝑏(𝑧 = 〈𝑎, 𝑏〉 ∧ (〈𝑎, 𝑏〉 ∈ 𝑠 ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧))) | 
| 187 | 186 | exbii 1848 | . . . . . . . . . . . 12
⊢
(∃𝑧(𝑧 ∈ (𝑠 ↾ {𝑎}) ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧) ↔ ∃𝑧∃𝑏(𝑧 = 〈𝑎, 𝑏〉 ∧ (〈𝑎, 𝑏〉 ∈ 𝑠 ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧))) | 
| 188 | 180, 187 | bitri 275 | . . . . . . . . . . 11
⊢
(∃𝑧 ∈
(𝑠 ↾ {𝑎})∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧 ↔ ∃𝑧∃𝑏(𝑧 = 〈𝑎, 𝑏〉 ∧ (〈𝑎, 𝑏〉 ∈ 𝑠 ∧ ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧))) | 
| 189 | 179, 188 | sylibr 234 | . . . . . . . . . 10
⊢
(∃𝑏 ∈
(𝑠 “ {𝑎})∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉 → ∃𝑧 ∈ (𝑠 ↾ {𝑎})∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧) | 
| 190 |  | ssrexv 4053 | . . . . . . . . . 10
⊢ ((𝑠 ↾ {𝑎}) ⊆ 𝑠 → (∃𝑧 ∈ (𝑠 ↾ {𝑎})∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧 → ∃𝑧 ∈ 𝑠 ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧)) | 
| 191 | 164, 189,
190 | mpsyl 68 | . . . . . . . . 9
⊢
(∃𝑏 ∈
(𝑠 “ {𝑎})∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇〈𝑎, 𝑏〉 → ∃𝑧 ∈ 𝑠 ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧) | 
| 192 | 163, 191 | syl6 35 | . . . . . . . 8
⊢ ((𝑆 Fr 𝐵 ∧ 𝑠 ⊆ (𝐴 × 𝐵) ∧ 𝑠 ≠ ∅) → ((𝑎 ∈ dom 𝑠 ∧ ∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎) → ∃𝑧 ∈ 𝑠 ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧)) | 
| 193 | 192 | expd 415 | . . . . . . 7
⊢ ((𝑆 Fr 𝐵 ∧ 𝑠 ⊆ (𝐴 × 𝐵) ∧ 𝑠 ≠ ∅) → (𝑎 ∈ dom 𝑠 → (∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎 → ∃𝑧 ∈ 𝑠 ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧))) | 
| 194 | 193 | rexlimdv 3153 | . . . . . 6
⊢ ((𝑆 Fr 𝐵 ∧ 𝑠 ⊆ (𝐴 × 𝐵) ∧ 𝑠 ≠ ∅) → (∃𝑎 ∈ dom 𝑠∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎 → ∃𝑧 ∈ 𝑠 ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧)) | 
| 195 | 194 | 3expib 1123 | . . . . 5
⊢ (𝑆 Fr 𝐵 → ((𝑠 ⊆ (𝐴 × 𝐵) ∧ 𝑠 ≠ ∅) → (∃𝑎 ∈ dom 𝑠∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎 → ∃𝑧 ∈ 𝑠 ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧))) | 
| 196 | 195 | adantl 481 | . . . 4
⊢ ((𝑅 Fr 𝐴 ∧ 𝑆 Fr 𝐵) → ((𝑠 ⊆ (𝐴 × 𝐵) ∧ 𝑠 ≠ ∅) → (∃𝑎 ∈ dom 𝑠∀𝑐 ∈ dom 𝑠 ¬ 𝑐𝑅𝑎 → ∃𝑧 ∈ 𝑠 ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧))) | 
| 197 | 33, 196 | mpdd 43 | . . 3
⊢ ((𝑅 Fr 𝐴 ∧ 𝑆 Fr 𝐵) → ((𝑠 ⊆ (𝐴 × 𝐵) ∧ 𝑠 ≠ ∅) → ∃𝑧 ∈ 𝑠 ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧)) | 
| 198 | 197 | alrimiv 1927 | . 2
⊢ ((𝑅 Fr 𝐴 ∧ 𝑆 Fr 𝐵) → ∀𝑠((𝑠 ⊆ (𝐴 × 𝐵) ∧ 𝑠 ≠ ∅) → ∃𝑧 ∈ 𝑠 ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧)) | 
| 199 |  | df-fr 5637 | . 2
⊢ (𝑇 Fr (𝐴 × 𝐵) ↔ ∀𝑠((𝑠 ⊆ (𝐴 × 𝐵) ∧ 𝑠 ≠ ∅) → ∃𝑧 ∈ 𝑠 ∀𝑤 ∈ 𝑠 ¬ 𝑤𝑇𝑧)) | 
| 200 | 198, 199 | sylibr 234 | 1
⊢ ((𝑅 Fr 𝐴 ∧ 𝑆 Fr 𝐵) → 𝑇 Fr (𝐴 × 𝐵)) |