| Step | Hyp | Ref | Expression | 
|---|
| 1 |  | relco 6126 | . 2
⊢ Rel
(𝐺 ∘ 𝐹) | 
| 2 |  | mptrel 5835 | . 2
⊢ Rel
(𝑥 ∈ 𝐴 ↦ 𝑇) | 
| 3 |  | fmptcof2.3 | . . . . . . . . . . . . 13
⊢
Ⅎ𝑥𝜑 | 
| 4 |  | fmptcof2.1 | . . . . . . . . . . . . 13
⊢
Ⅎ𝑥𝐴 | 
| 5 |  | fmptcof2.2 | . . . . . . . . . . . . 13
⊢
Ⅎ𝑥𝐵 | 
| 6 |  | fmptcof2.4 | . . . . . . . . . . . . . 14
⊢ (𝜑 → ∀𝑥 ∈ 𝐴 𝑅 ∈ 𝐵) | 
| 7 | 6 | r19.21bi 3251 | . . . . . . . . . . . . 13
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → 𝑅 ∈ 𝐵) | 
| 8 |  | eqid 2737 | . . . . . . . . . . . . 13
⊢ (𝑥 ∈ 𝐴 ↦ 𝑅) = (𝑥 ∈ 𝐴 ↦ 𝑅) | 
| 9 | 3, 4, 5, 7, 8 | fmptdF 32666 | . . . . . . . . . . . 12
⊢ (𝜑 → (𝑥 ∈ 𝐴 ↦ 𝑅):𝐴⟶𝐵) | 
| 10 |  | fmptcof2.5 | . . . . . . . . . . . . 13
⊢ (𝜑 → 𝐹 = (𝑥 ∈ 𝐴 ↦ 𝑅)) | 
| 11 | 10 | feq1d 6720 | . . . . . . . . . . . 12
⊢ (𝜑 → (𝐹:𝐴⟶𝐵 ↔ (𝑥 ∈ 𝐴 ↦ 𝑅):𝐴⟶𝐵)) | 
| 12 | 9, 11 | mpbird 257 | . . . . . . . . . . 11
⊢ (𝜑 → 𝐹:𝐴⟶𝐵) | 
| 13 | 12 | ffund 6740 | . . . . . . . . . 10
⊢ (𝜑 → Fun 𝐹) | 
| 14 |  | funbrfv 6957 | . . . . . . . . . . 11
⊢ (Fun
𝐹 → (𝑧𝐹𝑢 → (𝐹‘𝑧) = 𝑢)) | 
| 15 | 14 | imp 406 | . . . . . . . . . 10
⊢ ((Fun
𝐹 ∧ 𝑧𝐹𝑢) → (𝐹‘𝑧) = 𝑢) | 
| 16 | 13, 15 | sylan 580 | . . . . . . . . 9
⊢ ((𝜑 ∧ 𝑧𝐹𝑢) → (𝐹‘𝑧) = 𝑢) | 
| 17 | 16 | eqcomd 2743 | . . . . . . . 8
⊢ ((𝜑 ∧ 𝑧𝐹𝑢) → 𝑢 = (𝐹‘𝑧)) | 
| 18 | 17 | a1d 25 | . . . . . . 7
⊢ ((𝜑 ∧ 𝑧𝐹𝑢) → (𝑢𝐺𝑤 → 𝑢 = (𝐹‘𝑧))) | 
| 19 | 18 | expimpd 453 | . . . . . 6
⊢ (𝜑 → ((𝑧𝐹𝑢 ∧ 𝑢𝐺𝑤) → 𝑢 = (𝐹‘𝑧))) | 
| 20 | 19 | pm4.71rd 562 | . . . . 5
⊢ (𝜑 → ((𝑧𝐹𝑢 ∧ 𝑢𝐺𝑤) ↔ (𝑢 = (𝐹‘𝑧) ∧ (𝑧𝐹𝑢 ∧ 𝑢𝐺𝑤)))) | 
| 21 | 20 | exbidv 1921 | . . . 4
⊢ (𝜑 → (∃𝑢(𝑧𝐹𝑢 ∧ 𝑢𝐺𝑤) ↔ ∃𝑢(𝑢 = (𝐹‘𝑧) ∧ (𝑧𝐹𝑢 ∧ 𝑢𝐺𝑤)))) | 
| 22 |  | fvex 6919 | . . . . . 6
⊢ (𝐹‘𝑧) ∈ V | 
| 23 |  | breq2 5147 | . . . . . . 7
⊢ (𝑢 = (𝐹‘𝑧) → (𝑧𝐹𝑢 ↔ 𝑧𝐹(𝐹‘𝑧))) | 
| 24 |  | breq1 5146 | . . . . . . 7
⊢ (𝑢 = (𝐹‘𝑧) → (𝑢𝐺𝑤 ↔ (𝐹‘𝑧)𝐺𝑤)) | 
| 25 | 23, 24 | anbi12d 632 | . . . . . 6
⊢ (𝑢 = (𝐹‘𝑧) → ((𝑧𝐹𝑢 ∧ 𝑢𝐺𝑤) ↔ (𝑧𝐹(𝐹‘𝑧) ∧ (𝐹‘𝑧)𝐺𝑤))) | 
| 26 | 22, 25 | ceqsexv 3532 | . . . . 5
⊢
(∃𝑢(𝑢 = (𝐹‘𝑧) ∧ (𝑧𝐹𝑢 ∧ 𝑢𝐺𝑤)) ↔ (𝑧𝐹(𝐹‘𝑧) ∧ (𝐹‘𝑧)𝐺𝑤)) | 
| 27 |  | funfvbrb 7071 | . . . . . . . . 9
⊢ (Fun
𝐹 → (𝑧 ∈ dom 𝐹 ↔ 𝑧𝐹(𝐹‘𝑧))) | 
| 28 | 13, 27 | syl 17 | . . . . . . . 8
⊢ (𝜑 → (𝑧 ∈ dom 𝐹 ↔ 𝑧𝐹(𝐹‘𝑧))) | 
| 29 | 12 | fdmd 6746 | . . . . . . . . 9
⊢ (𝜑 → dom 𝐹 = 𝐴) | 
| 30 | 29 | eleq2d 2827 | . . . . . . . 8
⊢ (𝜑 → (𝑧 ∈ dom 𝐹 ↔ 𝑧 ∈ 𝐴)) | 
| 31 | 28, 30 | bitr3d 281 | . . . . . . 7
⊢ (𝜑 → (𝑧𝐹(𝐹‘𝑧) ↔ 𝑧 ∈ 𝐴)) | 
| 32 | 10 | fveq1d 6908 | . . . . . . . 8
⊢ (𝜑 → (𝐹‘𝑧) = ((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑧)) | 
| 33 |  | fmptcof2.6 | . . . . . . . 8
⊢ (𝜑 → 𝐺 = (𝑦 ∈ 𝐵 ↦ 𝑆)) | 
| 34 |  | eqidd 2738 | . . . . . . . 8
⊢ (𝜑 → 𝑤 = 𝑤) | 
| 35 | 32, 33, 34 | breq123d 5157 | . . . . . . 7
⊢ (𝜑 → ((𝐹‘𝑧)𝐺𝑤 ↔ ((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑧)(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤)) | 
| 36 | 31, 35 | anbi12d 632 | . . . . . 6
⊢ (𝜑 → ((𝑧𝐹(𝐹‘𝑧) ∧ (𝐹‘𝑧)𝐺𝑤) ↔ (𝑧 ∈ 𝐴 ∧ ((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑧)(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤))) | 
| 37 | 4 | nfcri 2897 | . . . . . . . . . 10
⊢
Ⅎ𝑥 𝑧 ∈ 𝐴 | 
| 38 |  | nffvmpt1 6917 | . . . . . . . . . . . . 13
⊢
Ⅎ𝑥((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑧) | 
| 39 |  | fmptcof2.x | . . . . . . . . . . . . . 14
⊢
Ⅎ𝑥𝑆 | 
| 40 | 5, 39 | nfmpt 5249 | . . . . . . . . . . . . 13
⊢
Ⅎ𝑥(𝑦 ∈ 𝐵 ↦ 𝑆) | 
| 41 |  | nfcv 2905 | . . . . . . . . . . . . 13
⊢
Ⅎ𝑥𝑤 | 
| 42 | 38, 40, 41 | nfbr 5190 | . . . . . . . . . . . 12
⊢
Ⅎ𝑥((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑧)(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤 | 
| 43 |  | nfcsb1v 3923 | . . . . . . . . . . . . 13
⊢
Ⅎ𝑥⦋𝑧 / 𝑥⦌𝑇 | 
| 44 | 43 | nfeq2 2923 | . . . . . . . . . . . 12
⊢
Ⅎ𝑥 𝑤 = ⦋𝑧 / 𝑥⦌𝑇 | 
| 45 | 42, 44 | nfbi 1903 | . . . . . . . . . . 11
⊢
Ⅎ𝑥(((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑧)(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤 ↔ 𝑤 = ⦋𝑧 / 𝑥⦌𝑇) | 
| 46 | 3, 45 | nfim 1896 | . . . . . . . . . 10
⊢
Ⅎ𝑥(𝜑 → (((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑧)(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤 ↔ 𝑤 = ⦋𝑧 / 𝑥⦌𝑇)) | 
| 47 | 37, 46 | nfim 1896 | . . . . . . . . 9
⊢
Ⅎ𝑥(𝑧 ∈ 𝐴 → (𝜑 → (((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑧)(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤 ↔ 𝑤 = ⦋𝑧 / 𝑥⦌𝑇))) | 
| 48 |  | eleq1w 2824 | . . . . . . . . . 10
⊢ (𝑥 = 𝑧 → (𝑥 ∈ 𝐴 ↔ 𝑧 ∈ 𝐴)) | 
| 49 |  | fveq2 6906 | . . . . . . . . . . . . 13
⊢ (𝑥 = 𝑧 → ((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑥) = ((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑧)) | 
| 50 | 49 | breq1d 5153 | . . . . . . . . . . . 12
⊢ (𝑥 = 𝑧 → (((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑥)(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤 ↔ ((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑧)(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤)) | 
| 51 |  | csbeq1a 3913 | . . . . . . . . . . . . 13
⊢ (𝑥 = 𝑧 → 𝑇 = ⦋𝑧 / 𝑥⦌𝑇) | 
| 52 | 51 | eqeq2d 2748 | . . . . . . . . . . . 12
⊢ (𝑥 = 𝑧 → (𝑤 = 𝑇 ↔ 𝑤 = ⦋𝑧 / 𝑥⦌𝑇)) | 
| 53 | 50, 52 | bibi12d 345 | . . . . . . . . . . 11
⊢ (𝑥 = 𝑧 → ((((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑥)(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤 ↔ 𝑤 = 𝑇) ↔ (((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑧)(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤 ↔ 𝑤 = ⦋𝑧 / 𝑥⦌𝑇))) | 
| 54 | 53 | imbi2d 340 | . . . . . . . . . 10
⊢ (𝑥 = 𝑧 → ((𝜑 → (((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑥)(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤 ↔ 𝑤 = 𝑇)) ↔ (𝜑 → (((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑧)(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤 ↔ 𝑤 = ⦋𝑧 / 𝑥⦌𝑇)))) | 
| 55 | 48, 54 | imbi12d 344 | . . . . . . . . 9
⊢ (𝑥 = 𝑧 → ((𝑥 ∈ 𝐴 → (𝜑 → (((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑥)(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤 ↔ 𝑤 = 𝑇))) ↔ (𝑧 ∈ 𝐴 → (𝜑 → (((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑧)(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤 ↔ 𝑤 = ⦋𝑧 / 𝑥⦌𝑇))))) | 
| 56 |  | vex 3484 | . . . . . . . . . . . 12
⊢ 𝑤 ∈ V | 
| 57 |  | nfv 1914 | . . . . . . . . . . . . . 14
⊢
Ⅎ𝑦 𝑅 ∈ 𝐵 | 
| 58 |  | fmptcof2.y | . . . . . . . . . . . . . . 15
⊢
Ⅎ𝑦𝑇 | 
| 59 | 58 | nfeq2 2923 | . . . . . . . . . . . . . 14
⊢
Ⅎ𝑦 𝑤 = 𝑇 | 
| 60 | 57, 59 | nfan 1899 | . . . . . . . . . . . . 13
⊢
Ⅎ𝑦(𝑅 ∈ 𝐵 ∧ 𝑤 = 𝑇) | 
| 61 |  | simpl 482 | . . . . . . . . . . . . . . 15
⊢ ((𝑦 = 𝑅 ∧ 𝑢 = 𝑤) → 𝑦 = 𝑅) | 
| 62 | 61 | eleq1d 2826 | . . . . . . . . . . . . . 14
⊢ ((𝑦 = 𝑅 ∧ 𝑢 = 𝑤) → (𝑦 ∈ 𝐵 ↔ 𝑅 ∈ 𝐵)) | 
| 63 |  | simpr 484 | . . . . . . . . . . . . . . 15
⊢ ((𝑦 = 𝑅 ∧ 𝑢 = 𝑤) → 𝑢 = 𝑤) | 
| 64 |  | fmptcof2.7 | . . . . . . . . . . . . . . . 16
⊢ (𝑦 = 𝑅 → 𝑆 = 𝑇) | 
| 65 | 64 | adantr 480 | . . . . . . . . . . . . . . 15
⊢ ((𝑦 = 𝑅 ∧ 𝑢 = 𝑤) → 𝑆 = 𝑇) | 
| 66 | 63, 65 | eqeq12d 2753 | . . . . . . . . . . . . . 14
⊢ ((𝑦 = 𝑅 ∧ 𝑢 = 𝑤) → (𝑢 = 𝑆 ↔ 𝑤 = 𝑇)) | 
| 67 | 62, 66 | anbi12d 632 | . . . . . . . . . . . . 13
⊢ ((𝑦 = 𝑅 ∧ 𝑢 = 𝑤) → ((𝑦 ∈ 𝐵 ∧ 𝑢 = 𝑆) ↔ (𝑅 ∈ 𝐵 ∧ 𝑤 = 𝑇))) | 
| 68 |  | df-mpt 5226 | . . . . . . . . . . . . 13
⊢ (𝑦 ∈ 𝐵 ↦ 𝑆) = {〈𝑦, 𝑢〉 ∣ (𝑦 ∈ 𝐵 ∧ 𝑢 = 𝑆)} | 
| 69 | 60, 67, 68 | brabgaf 32620 | . . . . . . . . . . . 12
⊢ ((𝑅 ∈ 𝐵 ∧ 𝑤 ∈ V) → (𝑅(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤 ↔ (𝑅 ∈ 𝐵 ∧ 𝑤 = 𝑇))) | 
| 70 | 7, 56, 69 | sylancl 586 | . . . . . . . . . . 11
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (𝑅(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤 ↔ (𝑅 ∈ 𝐵 ∧ 𝑤 = 𝑇))) | 
| 71 |  | simpr 484 | . . . . . . . . . . . . 13
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → 𝑥 ∈ 𝐴) | 
| 72 | 4 | fvmpt2f 7017 | . . . . . . . . . . . . 13
⊢ ((𝑥 ∈ 𝐴 ∧ 𝑅 ∈ 𝐵) → ((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑥) = 𝑅) | 
| 73 | 71, 7, 72 | syl2anc 584 | . . . . . . . . . . . 12
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → ((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑥) = 𝑅) | 
| 74 | 73 | breq1d 5153 | . . . . . . . . . . 11
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑥)(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤 ↔ 𝑅(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤)) | 
| 75 | 7 | biantrurd 532 | . . . . . . . . . . 11
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (𝑤 = 𝑇 ↔ (𝑅 ∈ 𝐵 ∧ 𝑤 = 𝑇))) | 
| 76 | 70, 74, 75 | 3bitr4d 311 | . . . . . . . . . 10
⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑥)(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤 ↔ 𝑤 = 𝑇)) | 
| 77 | 76 | expcom 413 | . . . . . . . . 9
⊢ (𝑥 ∈ 𝐴 → (𝜑 → (((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑥)(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤 ↔ 𝑤 = 𝑇))) | 
| 78 | 47, 55, 77 | chvarfv 2240 | . . . . . . . 8
⊢ (𝑧 ∈ 𝐴 → (𝜑 → (((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑧)(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤 ↔ 𝑤 = ⦋𝑧 / 𝑥⦌𝑇))) | 
| 79 | 78 | impcom 407 | . . . . . . 7
⊢ ((𝜑 ∧ 𝑧 ∈ 𝐴) → (((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑧)(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤 ↔ 𝑤 = ⦋𝑧 / 𝑥⦌𝑇)) | 
| 80 | 79 | pm5.32da 579 | . . . . . 6
⊢ (𝜑 → ((𝑧 ∈ 𝐴 ∧ ((𝑥 ∈ 𝐴 ↦ 𝑅)‘𝑧)(𝑦 ∈ 𝐵 ↦ 𝑆)𝑤) ↔ (𝑧 ∈ 𝐴 ∧ 𝑤 = ⦋𝑧 / 𝑥⦌𝑇))) | 
| 81 | 36, 80 | bitrd 279 | . . . . 5
⊢ (𝜑 → ((𝑧𝐹(𝐹‘𝑧) ∧ (𝐹‘𝑧)𝐺𝑤) ↔ (𝑧 ∈ 𝐴 ∧ 𝑤 = ⦋𝑧 / 𝑥⦌𝑇))) | 
| 82 | 26, 81 | bitrid 283 | . . . 4
⊢ (𝜑 → (∃𝑢(𝑢 = (𝐹‘𝑧) ∧ (𝑧𝐹𝑢 ∧ 𝑢𝐺𝑤)) ↔ (𝑧 ∈ 𝐴 ∧ 𝑤 = ⦋𝑧 / 𝑥⦌𝑇))) | 
| 83 | 21, 82 | bitrd 279 | . . 3
⊢ (𝜑 → (∃𝑢(𝑧𝐹𝑢 ∧ 𝑢𝐺𝑤) ↔ (𝑧 ∈ 𝐴 ∧ 𝑤 = ⦋𝑧 / 𝑥⦌𝑇))) | 
| 84 |  | vex 3484 | . . . 4
⊢ 𝑧 ∈ V | 
| 85 | 84, 56 | opelco 5882 | . . 3
⊢
(〈𝑧, 𝑤〉 ∈ (𝐺 ∘ 𝐹) ↔ ∃𝑢(𝑧𝐹𝑢 ∧ 𝑢𝐺𝑤)) | 
| 86 |  | df-mpt 5226 | . . . . 5
⊢ (𝑥 ∈ 𝐴 ↦ 𝑇) = {〈𝑥, 𝑣〉 ∣ (𝑥 ∈ 𝐴 ∧ 𝑣 = 𝑇)} | 
| 87 | 86 | eleq2i 2833 | . . . 4
⊢
(〈𝑧, 𝑤〉 ∈ (𝑥 ∈ 𝐴 ↦ 𝑇) ↔ 〈𝑧, 𝑤〉 ∈ {〈𝑥, 𝑣〉 ∣ (𝑥 ∈ 𝐴 ∧ 𝑣 = 𝑇)}) | 
| 88 | 43 | nfeq2 2923 | . . . . . 6
⊢
Ⅎ𝑥 𝑣 = ⦋𝑧 / 𝑥⦌𝑇 | 
| 89 | 37, 88 | nfan 1899 | . . . . 5
⊢
Ⅎ𝑥(𝑧 ∈ 𝐴 ∧ 𝑣 = ⦋𝑧 / 𝑥⦌𝑇) | 
| 90 |  | nfv 1914 | . . . . 5
⊢
Ⅎ𝑣(𝑧 ∈ 𝐴 ∧ 𝑤 = ⦋𝑧 / 𝑥⦌𝑇) | 
| 91 | 51 | eqeq2d 2748 | . . . . . 6
⊢ (𝑥 = 𝑧 → (𝑣 = 𝑇 ↔ 𝑣 = ⦋𝑧 / 𝑥⦌𝑇)) | 
| 92 | 48, 91 | anbi12d 632 | . . . . 5
⊢ (𝑥 = 𝑧 → ((𝑥 ∈ 𝐴 ∧ 𝑣 = 𝑇) ↔ (𝑧 ∈ 𝐴 ∧ 𝑣 = ⦋𝑧 / 𝑥⦌𝑇))) | 
| 93 |  | eqeq1 2741 | . . . . . 6
⊢ (𝑣 = 𝑤 → (𝑣 = ⦋𝑧 / 𝑥⦌𝑇 ↔ 𝑤 = ⦋𝑧 / 𝑥⦌𝑇)) | 
| 94 | 93 | anbi2d 630 | . . . . 5
⊢ (𝑣 = 𝑤 → ((𝑧 ∈ 𝐴 ∧ 𝑣 = ⦋𝑧 / 𝑥⦌𝑇) ↔ (𝑧 ∈ 𝐴 ∧ 𝑤 = ⦋𝑧 / 𝑥⦌𝑇))) | 
| 95 | 89, 90, 84, 56, 92, 94 | opelopabf 5550 | . . . 4
⊢
(〈𝑧, 𝑤〉 ∈ {〈𝑥, 𝑣〉 ∣ (𝑥 ∈ 𝐴 ∧ 𝑣 = 𝑇)} ↔ (𝑧 ∈ 𝐴 ∧ 𝑤 = ⦋𝑧 / 𝑥⦌𝑇)) | 
| 96 | 87, 95 | bitri 275 | . . 3
⊢
(〈𝑧, 𝑤〉 ∈ (𝑥 ∈ 𝐴 ↦ 𝑇) ↔ (𝑧 ∈ 𝐴 ∧ 𝑤 = ⦋𝑧 / 𝑥⦌𝑇)) | 
| 97 | 83, 85, 96 | 3bitr4g 314 | . 2
⊢ (𝜑 → (〈𝑧, 𝑤〉 ∈ (𝐺 ∘ 𝐹) ↔ 〈𝑧, 𝑤〉 ∈ (𝑥 ∈ 𝐴 ↦ 𝑇))) | 
| 98 | 1, 2, 97 | eqrelrdv 5802 | 1
⊢ (𝜑 → (𝐺 ∘ 𝐹) = (𝑥 ∈ 𝐴 ↦ 𝑇)) |