| Step | Hyp | Ref
| Expression |
| 1 | | eqid 2622 |
. . . . . 6
⊢
(glb‘𝐾) =
(glb‘𝐾) |
| 2 | | dihmeetlem2.m |
. . . . . 6
⊢ ∧ =
(meet‘𝐾) |
| 3 | | simp1l 1085 |
. . . . . 6
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → 𝐾 ∈ HL) |
| 4 | | simp2l 1087 |
. . . . . 6
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → 𝑋 ∈ 𝐵) |
| 5 | | simp3l 1089 |
. . . . . 6
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → 𝑌 ∈ 𝐵) |
| 6 | 1, 2, 3, 4, 5 | meetval 17019 |
. . . . 5
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → (𝑋 ∧ 𝑌) = ((glb‘𝐾)‘{𝑋, 𝑌})) |
| 7 | 6 | fveq2d 6195 |
. . . 4
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → (((DIsoB‘𝐾)‘𝑊)‘(𝑋 ∧ 𝑌)) = (((DIsoB‘𝐾)‘𝑊)‘((glb‘𝐾)‘{𝑋, 𝑌}))) |
| 8 | | simp1 1061 |
. . . . 5
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → (𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻)) |
| 9 | | dihmeetlem2.b |
. . . . . . . . 9
⊢ 𝐵 = (Base‘𝐾) |
| 10 | | dihmeetlem2.l |
. . . . . . . . 9
⊢ ≤ =
(le‘𝐾) |
| 11 | | dihmeetlem2.h |
. . . . . . . . 9
⊢ 𝐻 = (LHyp‘𝐾) |
| 12 | | eqid 2622 |
. . . . . . . . 9
⊢
((DIsoB‘𝐾)‘𝑊) = ((DIsoB‘𝐾)‘𝑊) |
| 13 | 9, 10, 11, 12 | dibeldmN 36447 |
. . . . . . . 8
⊢ ((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) → (𝑋 ∈ dom ((DIsoB‘𝐾)‘𝑊) ↔ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊))) |
| 14 | 13 | biimpar 502 |
. . . . . . 7
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊)) → 𝑋 ∈ dom ((DIsoB‘𝐾)‘𝑊)) |
| 15 | 14 | 3adant3 1081 |
. . . . . 6
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → 𝑋 ∈ dom ((DIsoB‘𝐾)‘𝑊)) |
| 16 | 9, 10, 11, 12 | dibeldmN 36447 |
. . . . . . . 8
⊢ ((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) → (𝑌 ∈ dom ((DIsoB‘𝐾)‘𝑊) ↔ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊))) |
| 17 | 16 | biimpar 502 |
. . . . . . 7
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → 𝑌 ∈ dom ((DIsoB‘𝐾)‘𝑊)) |
| 18 | 17 | 3adant2 1080 |
. . . . . 6
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → 𝑌 ∈ dom ((DIsoB‘𝐾)‘𝑊)) |
| 19 | | prssg 4350 |
. . . . . . 7
⊢ ((𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵) → ((𝑋 ∈ dom ((DIsoB‘𝐾)‘𝑊) ∧ 𝑌 ∈ dom ((DIsoB‘𝐾)‘𝑊)) ↔ {𝑋, 𝑌} ⊆ dom ((DIsoB‘𝐾)‘𝑊))) |
| 20 | 4, 5, 19 | syl2anc 693 |
. . . . . 6
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → ((𝑋 ∈ dom ((DIsoB‘𝐾)‘𝑊) ∧ 𝑌 ∈ dom ((DIsoB‘𝐾)‘𝑊)) ↔ {𝑋, 𝑌} ⊆ dom ((DIsoB‘𝐾)‘𝑊))) |
| 21 | 15, 18, 20 | mpbi2and 956 |
. . . . 5
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → {𝑋, 𝑌} ⊆ dom ((DIsoB‘𝐾)‘𝑊)) |
| 22 | | prnzg 4311 |
. . . . . 6
⊢ (𝑋 ∈ 𝐵 → {𝑋, 𝑌} ≠ ∅) |
| 23 | 4, 22 | syl 17 |
. . . . 5
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → {𝑋, 𝑌} ≠ ∅) |
| 24 | 1, 11, 12 | dibglbN 36455 |
. . . . 5
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ ({𝑋, 𝑌} ⊆ dom ((DIsoB‘𝐾)‘𝑊) ∧ {𝑋, 𝑌} ≠ ∅)) → (((DIsoB‘𝐾)‘𝑊)‘((glb‘𝐾)‘{𝑋, 𝑌})) = ∩
𝑥 ∈ {𝑋, 𝑌} (((DIsoB‘𝐾)‘𝑊)‘𝑥)) |
| 25 | 8, 21, 23, 24 | syl12anc 1324 |
. . . 4
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → (((DIsoB‘𝐾)‘𝑊)‘((glb‘𝐾)‘{𝑋, 𝑌})) = ∩
𝑥 ∈ {𝑋, 𝑌} (((DIsoB‘𝐾)‘𝑊)‘𝑥)) |
| 26 | 7, 25 | eqtrd 2656 |
. . 3
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → (((DIsoB‘𝐾)‘𝑊)‘(𝑋 ∧ 𝑌)) = ∩
𝑥 ∈ {𝑋, 𝑌} (((DIsoB‘𝐾)‘𝑊)‘𝑥)) |
| 27 | | hllat 34650 |
. . . . . 6
⊢ (𝐾 ∈ HL → 𝐾 ∈ Lat) |
| 28 | 3, 27 | syl 17 |
. . . . 5
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → 𝐾 ∈ Lat) |
| 29 | 9, 2 | latmcl 17052 |
. . . . 5
⊢ ((𝐾 ∈ Lat ∧ 𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵) → (𝑋 ∧ 𝑌) ∈ 𝐵) |
| 30 | 28, 4, 5, 29 | syl3anc 1326 |
. . . 4
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → (𝑋 ∧ 𝑌) ∈ 𝐵) |
| 31 | | simp1r 1086 |
. . . . . 6
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → 𝑊 ∈ 𝐻) |
| 32 | 9, 11 | lhpbase 35284 |
. . . . . 6
⊢ (𝑊 ∈ 𝐻 → 𝑊 ∈ 𝐵) |
| 33 | 31, 32 | syl 17 |
. . . . 5
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → 𝑊 ∈ 𝐵) |
| 34 | 9, 10, 2 | latmle1 17076 |
. . . . . 6
⊢ ((𝐾 ∈ Lat ∧ 𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵) → (𝑋 ∧ 𝑌) ≤ 𝑋) |
| 35 | 28, 4, 5, 34 | syl3anc 1326 |
. . . . 5
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → (𝑋 ∧ 𝑌) ≤ 𝑋) |
| 36 | | simp2r 1088 |
. . . . 5
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → 𝑋 ≤ 𝑊) |
| 37 | 9, 10, 28, 30, 4, 33, 35, 36 | lattrd 17058 |
. . . 4
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → (𝑋 ∧ 𝑌) ≤ 𝑊) |
| 38 | | dihmeetlem2.i |
. . . . 5
⊢ 𝐼 = ((DIsoH‘𝐾)‘𝑊) |
| 39 | 9, 10, 11, 38, 12 | dihvalb 36526 |
. . . 4
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ ((𝑋 ∧ 𝑌) ∈ 𝐵 ∧ (𝑋 ∧ 𝑌) ≤ 𝑊)) → (𝐼‘(𝑋 ∧ 𝑌)) = (((DIsoB‘𝐾)‘𝑊)‘(𝑋 ∧ 𝑌))) |
| 40 | 8, 30, 37, 39 | syl12anc 1324 |
. . 3
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → (𝐼‘(𝑋 ∧ 𝑌)) = (((DIsoB‘𝐾)‘𝑊)‘(𝑋 ∧ 𝑌))) |
| 41 | | simpl1 1064 |
. . . . 5
⊢ ((((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) ∧ 𝑥 ∈ {𝑋, 𝑌}) → (𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻)) |
| 42 | | vex 3203 |
. . . . . . 7
⊢ 𝑥 ∈ V |
| 43 | 42 | elpr 4198 |
. . . . . 6
⊢ (𝑥 ∈ {𝑋, 𝑌} ↔ (𝑥 = 𝑋 ∨ 𝑥 = 𝑌)) |
| 44 | | simpl2 1065 |
. . . . . . . 8
⊢ ((((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) ∧ 𝑥 = 𝑋) → (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊)) |
| 45 | | eleq1 2689 |
. . . . . . . . . 10
⊢ (𝑥 = 𝑋 → (𝑥 ∈ 𝐵 ↔ 𝑋 ∈ 𝐵)) |
| 46 | | breq1 4656 |
. . . . . . . . . 10
⊢ (𝑥 = 𝑋 → (𝑥 ≤ 𝑊 ↔ 𝑋 ≤ 𝑊)) |
| 47 | 45, 46 | anbi12d 747 |
. . . . . . . . 9
⊢ (𝑥 = 𝑋 → ((𝑥 ∈ 𝐵 ∧ 𝑥 ≤ 𝑊) ↔ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊))) |
| 48 | 47 | adantl 482 |
. . . . . . . 8
⊢ ((((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) ∧ 𝑥 = 𝑋) → ((𝑥 ∈ 𝐵 ∧ 𝑥 ≤ 𝑊) ↔ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊))) |
| 49 | 44, 48 | mpbird 247 |
. . . . . . 7
⊢ ((((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) ∧ 𝑥 = 𝑋) → (𝑥 ∈ 𝐵 ∧ 𝑥 ≤ 𝑊)) |
| 50 | | simpl3 1066 |
. . . . . . . 8
⊢ ((((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) ∧ 𝑥 = 𝑌) → (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) |
| 51 | | eleq1 2689 |
. . . . . . . . . 10
⊢ (𝑥 = 𝑌 → (𝑥 ∈ 𝐵 ↔ 𝑌 ∈ 𝐵)) |
| 52 | | breq1 4656 |
. . . . . . . . . 10
⊢ (𝑥 = 𝑌 → (𝑥 ≤ 𝑊 ↔ 𝑌 ≤ 𝑊)) |
| 53 | 51, 52 | anbi12d 747 |
. . . . . . . . 9
⊢ (𝑥 = 𝑌 → ((𝑥 ∈ 𝐵 ∧ 𝑥 ≤ 𝑊) ↔ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊))) |
| 54 | 53 | adantl 482 |
. . . . . . . 8
⊢ ((((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) ∧ 𝑥 = 𝑌) → ((𝑥 ∈ 𝐵 ∧ 𝑥 ≤ 𝑊) ↔ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊))) |
| 55 | 50, 54 | mpbird 247 |
. . . . . . 7
⊢ ((((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) ∧ 𝑥 = 𝑌) → (𝑥 ∈ 𝐵 ∧ 𝑥 ≤ 𝑊)) |
| 56 | 49, 55 | jaodan 826 |
. . . . . 6
⊢ ((((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) ∧ (𝑥 = 𝑋 ∨ 𝑥 = 𝑌)) → (𝑥 ∈ 𝐵 ∧ 𝑥 ≤ 𝑊)) |
| 57 | 43, 56 | sylan2b 492 |
. . . . 5
⊢ ((((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) ∧ 𝑥 ∈ {𝑋, 𝑌}) → (𝑥 ∈ 𝐵 ∧ 𝑥 ≤ 𝑊)) |
| 58 | 9, 10, 11, 38, 12 | dihvalb 36526 |
. . . . 5
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑥 ∈ 𝐵 ∧ 𝑥 ≤ 𝑊)) → (𝐼‘𝑥) = (((DIsoB‘𝐾)‘𝑊)‘𝑥)) |
| 59 | 41, 57, 58 | syl2anc 693 |
. . . 4
⊢ ((((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) ∧ 𝑥 ∈ {𝑋, 𝑌}) → (𝐼‘𝑥) = (((DIsoB‘𝐾)‘𝑊)‘𝑥)) |
| 60 | 59 | iineq2dv 4543 |
. . 3
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → ∩ 𝑥 ∈ {𝑋, 𝑌} (𝐼‘𝑥) = ∩ 𝑥 ∈ {𝑋, 𝑌} (((DIsoB‘𝐾)‘𝑊)‘𝑥)) |
| 61 | 26, 40, 60 | 3eqtr4d 2666 |
. 2
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → (𝐼‘(𝑋 ∧ 𝑌)) = ∩
𝑥 ∈ {𝑋, 𝑌} (𝐼‘𝑥)) |
| 62 | | fveq2 6191 |
. . . 4
⊢ (𝑥 = 𝑋 → (𝐼‘𝑥) = (𝐼‘𝑋)) |
| 63 | | fveq2 6191 |
. . . 4
⊢ (𝑥 = 𝑌 → (𝐼‘𝑥) = (𝐼‘𝑌)) |
| 64 | 62, 63 | iinxprg 4601 |
. . 3
⊢ ((𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵) → ∩
𝑥 ∈ {𝑋, 𝑌} (𝐼‘𝑥) = ((𝐼‘𝑋) ∩ (𝐼‘𝑌))) |
| 65 | 4, 5, 64 | syl2anc 693 |
. 2
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → ∩ 𝑥 ∈ {𝑋, 𝑌} (𝐼‘𝑥) = ((𝐼‘𝑋) ∩ (𝐼‘𝑌))) |
| 66 | 61, 65 | eqtrd 2656 |
1
⊢ (((𝐾 ∈ HL ∧ 𝑊 ∈ 𝐻) ∧ (𝑋 ∈ 𝐵 ∧ 𝑋 ≤ 𝑊) ∧ (𝑌 ∈ 𝐵 ∧ 𝑌 ≤ 𝑊)) → (𝐼‘(𝑋 ∧ 𝑌)) = ((𝐼‘𝑋) ∩ (𝐼‘𝑌))) |