| Step | Hyp | Ref
 | Expression | 
| 1 |   | offval.1 | 
. . . 4
⊢ (𝜑 → 𝐹 Fn 𝐴) | 
| 2 |   | offval.3 | 
. . . 4
⊢ (𝜑 → 𝐴 ∈ 𝑉) | 
| 3 |   | fnex 5784 | 
. . . 4
⊢ ((𝐹 Fn 𝐴 ∧ 𝐴 ∈ 𝑉) → 𝐹 ∈ V) | 
| 4 | 1, 2, 3 | syl2anc 411 | 
. . 3
⊢ (𝜑 → 𝐹 ∈ V) | 
| 5 |   | offval.2 | 
. . . 4
⊢ (𝜑 → 𝐺 Fn 𝐵) | 
| 6 |   | offval.4 | 
. . . 4
⊢ (𝜑 → 𝐵 ∈ 𝑊) | 
| 7 |   | fnex 5784 | 
. . . 4
⊢ ((𝐺 Fn 𝐵 ∧ 𝐵 ∈ 𝑊) → 𝐺 ∈ V) | 
| 8 | 5, 6, 7 | syl2anc 411 | 
. . 3
⊢ (𝜑 → 𝐺 ∈ V) | 
| 9 |   | dmeq 4866 | 
. . . . . 6
⊢ (𝑓 = 𝐹 → dom 𝑓 = dom 𝐹) | 
| 10 |   | dmeq 4866 | 
. . . . . 6
⊢ (𝑔 = 𝐺 → dom 𝑔 = dom 𝐺) | 
| 11 | 9, 10 | ineqan12d 3366 | 
. . . . 5
⊢ ((𝑓 = 𝐹 ∧ 𝑔 = 𝐺) → (dom 𝑓 ∩ dom 𝑔) = (dom 𝐹 ∩ dom 𝐺)) | 
| 12 |   | fveq1 5557 | 
. . . . . 6
⊢ (𝑓 = 𝐹 → (𝑓‘𝑥) = (𝐹‘𝑥)) | 
| 13 |   | fveq1 5557 | 
. . . . . 6
⊢ (𝑔 = 𝐺 → (𝑔‘𝑥) = (𝐺‘𝑥)) | 
| 14 | 12, 13 | breqan12d 4049 | 
. . . . 5
⊢ ((𝑓 = 𝐹 ∧ 𝑔 = 𝐺) → ((𝑓‘𝑥)𝑅(𝑔‘𝑥) ↔ (𝐹‘𝑥)𝑅(𝐺‘𝑥))) | 
| 15 | 11, 14 | raleqbidv 2709 | 
. . . 4
⊢ ((𝑓 = 𝐹 ∧ 𝑔 = 𝐺) → (∀𝑥 ∈ (dom 𝑓 ∩ dom 𝑔)(𝑓‘𝑥)𝑅(𝑔‘𝑥) ↔ ∀𝑥 ∈ (dom 𝐹 ∩ dom 𝐺)(𝐹‘𝑥)𝑅(𝐺‘𝑥))) | 
| 16 |   | df-ofr 6136 | 
. . . 4
⊢ 
∘𝑟 𝑅 = {〈𝑓, 𝑔〉 ∣ ∀𝑥 ∈ (dom 𝑓 ∩ dom 𝑔)(𝑓‘𝑥)𝑅(𝑔‘𝑥)} | 
| 17 | 15, 16 | brabga 4298 | 
. . 3
⊢ ((𝐹 ∈ V ∧ 𝐺 ∈ V) → (𝐹 ∘𝑟
𝑅𝐺 ↔ ∀𝑥 ∈ (dom 𝐹 ∩ dom 𝐺)(𝐹‘𝑥)𝑅(𝐺‘𝑥))) | 
| 18 | 4, 8, 17 | syl2anc 411 | 
. 2
⊢ (𝜑 → (𝐹 ∘𝑟 𝑅𝐺 ↔ ∀𝑥 ∈ (dom 𝐹 ∩ dom 𝐺)(𝐹‘𝑥)𝑅(𝐺‘𝑥))) | 
| 19 |   | fndm 5357 | 
. . . . . 6
⊢ (𝐹 Fn 𝐴 → dom 𝐹 = 𝐴) | 
| 20 | 1, 19 | syl 14 | 
. . . . 5
⊢ (𝜑 → dom 𝐹 = 𝐴) | 
| 21 |   | fndm 5357 | 
. . . . . 6
⊢ (𝐺 Fn 𝐵 → dom 𝐺 = 𝐵) | 
| 22 | 5, 21 | syl 14 | 
. . . . 5
⊢ (𝜑 → dom 𝐺 = 𝐵) | 
| 23 | 20, 22 | ineq12d 3365 | 
. . . 4
⊢ (𝜑 → (dom 𝐹 ∩ dom 𝐺) = (𝐴 ∩ 𝐵)) | 
| 24 |   | offval.5 | 
. . . 4
⊢ (𝐴 ∩ 𝐵) = 𝑆 | 
| 25 | 23, 24 | eqtrdi 2245 | 
. . 3
⊢ (𝜑 → (dom 𝐹 ∩ dom 𝐺) = 𝑆) | 
| 26 | 25 | raleqdv 2699 | 
. 2
⊢ (𝜑 → (∀𝑥 ∈ (dom 𝐹 ∩ dom 𝐺)(𝐹‘𝑥)𝑅(𝐺‘𝑥) ↔ ∀𝑥 ∈ 𝑆 (𝐹‘𝑥)𝑅(𝐺‘𝑥))) | 
| 27 |   | inss1 3383 | 
. . . . . . 7
⊢ (𝐴 ∩ 𝐵) ⊆ 𝐴 | 
| 28 | 24, 27 | eqsstrri 3216 | 
. . . . . 6
⊢ 𝑆 ⊆ 𝐴 | 
| 29 | 28 | sseli 3179 | 
. . . . 5
⊢ (𝑥 ∈ 𝑆 → 𝑥 ∈ 𝐴) | 
| 30 |   | offval.6 | 
. . . . 5
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (𝐹‘𝑥) = 𝐶) | 
| 31 | 29, 30 | sylan2 286 | 
. . . 4
⊢ ((𝜑 ∧ 𝑥 ∈ 𝑆) → (𝐹‘𝑥) = 𝐶) | 
| 32 |   | inss2 3384 | 
. . . . . . 7
⊢ (𝐴 ∩ 𝐵) ⊆ 𝐵 | 
| 33 | 24, 32 | eqsstrri 3216 | 
. . . . . 6
⊢ 𝑆 ⊆ 𝐵 | 
| 34 | 33 | sseli 3179 | 
. . . . 5
⊢ (𝑥 ∈ 𝑆 → 𝑥 ∈ 𝐵) | 
| 35 |   | offval.7 | 
. . . . 5
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐵) → (𝐺‘𝑥) = 𝐷) | 
| 36 | 34, 35 | sylan2 286 | 
. . . 4
⊢ ((𝜑 ∧ 𝑥 ∈ 𝑆) → (𝐺‘𝑥) = 𝐷) | 
| 37 | 31, 36 | breq12d 4046 | 
. . 3
⊢ ((𝜑 ∧ 𝑥 ∈ 𝑆) → ((𝐹‘𝑥)𝑅(𝐺‘𝑥) ↔ 𝐶𝑅𝐷)) | 
| 38 | 37 | ralbidva 2493 | 
. 2
⊢ (𝜑 → (∀𝑥 ∈ 𝑆 (𝐹‘𝑥)𝑅(𝐺‘𝑥) ↔ ∀𝑥 ∈ 𝑆 𝐶𝑅𝐷)) | 
| 39 | 18, 26, 38 | 3bitrd 214 | 
1
⊢ (𝜑 → (𝐹 ∘𝑟 𝑅𝐺 ↔ ∀𝑥 ∈ 𝑆 𝐶𝑅𝐷)) |