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Description: A basic open set of the compact-open topology. (Contributed by Mario Carneiro, 19-Mar-2015)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | xkoopn.x | ⊢ 𝑋 = ∪ 𝑅 | |
| xkoopn.r | ⊢ ( 𝜑 → 𝑅 ∈ Top ) | ||
| xkoopn.s | ⊢ ( 𝜑 → 𝑆 ∈ Top ) | ||
| xkoopn.a | ⊢ ( 𝜑 → 𝐴 ⊆ 𝑋 ) | ||
| xkoopn.c | ⊢ ( 𝜑 → ( 𝑅 ↾t 𝐴 ) ∈ Comp ) | ||
| xkoopn.u | ⊢ ( 𝜑 → 𝑈 ∈ 𝑆 ) | ||
| Assertion | xkoopn | ⊢ ( 𝜑 → { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } ∈ ( 𝑆 ↑ko 𝑅 ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | xkoopn.x | ⊢ 𝑋 = ∪ 𝑅 | |
| 2 | xkoopn.r | ⊢ ( 𝜑 → 𝑅 ∈ Top ) | |
| 3 | xkoopn.s | ⊢ ( 𝜑 → 𝑆 ∈ Top ) | |
| 4 | xkoopn.a | ⊢ ( 𝜑 → 𝐴 ⊆ 𝑋 ) | |
| 5 | xkoopn.c | ⊢ ( 𝜑 → ( 𝑅 ↾t 𝐴 ) ∈ Comp ) | |
| 6 | xkoopn.u | ⊢ ( 𝜑 → 𝑈 ∈ 𝑆 ) | |
| 7 | ovex | ⊢ ( 𝑅 Cn 𝑆 ) ∈ V | |
| 8 | 7 | pwex | ⊢ 𝒫 ( 𝑅 Cn 𝑆 ) ∈ V |
| 9 | eqid | ⊢ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } = { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } | |
| 10 | eqid | ⊢ ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) = ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) | |
| 11 | 1 9 10 | xkotf | ⊢ ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) : ( { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } × 𝑆 ) ⟶ 𝒫 ( 𝑅 Cn 𝑆 ) |
| 12 | frn | ⊢ ( ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) : ( { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } × 𝑆 ) ⟶ 𝒫 ( 𝑅 Cn 𝑆 ) → ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ⊆ 𝒫 ( 𝑅 Cn 𝑆 ) ) | |
| 13 | 11 12 | ax-mp | ⊢ ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ⊆ 𝒫 ( 𝑅 Cn 𝑆 ) |
| 14 | 8 13 | ssexi | ⊢ ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ∈ V |
| 15 | ssfii | ⊢ ( ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ∈ V → ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ⊆ ( fi ‘ ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ) ) | |
| 16 | 14 15 | ax-mp | ⊢ ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ⊆ ( fi ‘ ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ) |
| 17 | fvex | ⊢ ( fi ‘ ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ) ∈ V | |
| 18 | bastg | ⊢ ( ( fi ‘ ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ) ∈ V → ( fi ‘ ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ) ⊆ ( topGen ‘ ( fi ‘ ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ) ) ) | |
| 19 | 17 18 | ax-mp | ⊢ ( fi ‘ ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ) ⊆ ( topGen ‘ ( fi ‘ ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ) ) |
| 20 | 16 19 | sstri | ⊢ ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ⊆ ( topGen ‘ ( fi ‘ ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ) ) |
| 21 | oveq2 | ⊢ ( 𝑥 = 𝐴 → ( 𝑅 ↾t 𝑥 ) = ( 𝑅 ↾t 𝐴 ) ) | |
| 22 | 21 | eleq1d | ⊢ ( 𝑥 = 𝐴 → ( ( 𝑅 ↾t 𝑥 ) ∈ Comp ↔ ( 𝑅 ↾t 𝐴 ) ∈ Comp ) ) |
| 23 | 1 | topopn | ⊢ ( 𝑅 ∈ Top → 𝑋 ∈ 𝑅 ) |
| 24 | elpw2g | ⊢ ( 𝑋 ∈ 𝑅 → ( 𝐴 ∈ 𝒫 𝑋 ↔ 𝐴 ⊆ 𝑋 ) ) | |
| 25 | 2 23 24 | 3syl | ⊢ ( 𝜑 → ( 𝐴 ∈ 𝒫 𝑋 ↔ 𝐴 ⊆ 𝑋 ) ) |
| 26 | 4 25 | mpbird | ⊢ ( 𝜑 → 𝐴 ∈ 𝒫 𝑋 ) |
| 27 | 22 26 5 | elrabd | ⊢ ( 𝜑 → 𝐴 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } ) |
| 28 | eqidd | ⊢ ( 𝜑 → { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } = { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } ) | |
| 29 | imaeq2 | ⊢ ( 𝑘 = 𝐴 → ( 𝑓 “ 𝑘 ) = ( 𝑓 “ 𝐴 ) ) | |
| 30 | 29 | sseq1d | ⊢ ( 𝑘 = 𝐴 → ( ( 𝑓 “ 𝑘 ) ⊆ 𝑣 ↔ ( 𝑓 “ 𝐴 ) ⊆ 𝑣 ) ) |
| 31 | 30 | rabbidv | ⊢ ( 𝑘 = 𝐴 → { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } = { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑣 } ) |
| 32 | 31 | eqeq2d | ⊢ ( 𝑘 = 𝐴 → ( { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } = { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ↔ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } = { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑣 } ) ) |
| 33 | sseq2 | ⊢ ( 𝑣 = 𝑈 → ( ( 𝑓 “ 𝐴 ) ⊆ 𝑣 ↔ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 ) ) | |
| 34 | 33 | rabbidv | ⊢ ( 𝑣 = 𝑈 → { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑣 } = { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } ) |
| 35 | 34 | eqeq2d | ⊢ ( 𝑣 = 𝑈 → ( { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } = { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑣 } ↔ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } = { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } ) ) |
| 36 | 32 35 | rspc2ev | ⊢ ( ( 𝐴 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } ∧ 𝑈 ∈ 𝑆 ∧ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } = { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } ) → ∃ 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } ∃ 𝑣 ∈ 𝑆 { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } = { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) |
| 37 | 27 6 28 36 | syl3anc | ⊢ ( 𝜑 → ∃ 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } ∃ 𝑣 ∈ 𝑆 { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } = { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) |
| 38 | 7 | rabex | ⊢ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } ∈ V |
| 39 | eqeq1 | ⊢ ( 𝑦 = { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } → ( 𝑦 = { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ↔ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } = { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ) | |
| 40 | 39 | 2rexbidv | ⊢ ( 𝑦 = { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } → ( ∃ 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } ∃ 𝑣 ∈ 𝑆 𝑦 = { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ↔ ∃ 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } ∃ 𝑣 ∈ 𝑆 { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } = { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ) |
| 41 | 10 | rnmpo | ⊢ ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) = { 𝑦 ∣ ∃ 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } ∃ 𝑣 ∈ 𝑆 𝑦 = { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } } |
| 42 | 38 40 41 | elab2 | ⊢ ( { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } ∈ ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ↔ ∃ 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } ∃ 𝑣 ∈ 𝑆 { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } = { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) |
| 43 | 37 42 | sylibr | ⊢ ( 𝜑 → { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } ∈ ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ) |
| 44 | 20 43 | sselid | ⊢ ( 𝜑 → { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } ∈ ( topGen ‘ ( fi ‘ ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ) ) ) |
| 45 | 1 9 10 | xkoval | ⊢ ( ( 𝑅 ∈ Top ∧ 𝑆 ∈ Top ) → ( 𝑆 ↑ko 𝑅 ) = ( topGen ‘ ( fi ‘ ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ) ) ) |
| 46 | 2 3 45 | syl2anc | ⊢ ( 𝜑 → ( 𝑆 ↑ko 𝑅 ) = ( topGen ‘ ( fi ‘ ran ( 𝑘 ∈ { 𝑥 ∈ 𝒫 𝑋 ∣ ( 𝑅 ↾t 𝑥 ) ∈ Comp } , 𝑣 ∈ 𝑆 ↦ { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝑘 ) ⊆ 𝑣 } ) ) ) ) |
| 47 | 44 46 | eleqtrrd | ⊢ ( 𝜑 → { 𝑓 ∈ ( 𝑅 Cn 𝑆 ) ∣ ( 𝑓 “ 𝐴 ) ⊆ 𝑈 } ∈ ( 𝑆 ↑ko 𝑅 ) ) |