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Mirrors > Home > MPE Home > Th. List > 2ndcredom | Structured version Visualization version GIF version |
Description: A second-countable space has at most the cardinality of the continuum. (Contributed by Mario Carneiro, 9-Apr-2015.) |
Ref | Expression |
---|---|
2ndcredom | ⊢ (𝐽 ∈ 2ndω → 𝐽 ≼ ℝ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | is2ndc 23272 | . 2 ⊢ (𝐽 ∈ 2ndω ↔ ∃𝑥 ∈ TopBases (𝑥 ≼ ω ∧ (topGen‘𝑥) = 𝐽)) | |
2 | tgdom 22803 | . . . . . 6 ⊢ (𝑥 ∈ TopBases → (topGen‘𝑥) ≼ 𝒫 𝑥) | |
3 | simpr 484 | . . . . . . . . 9 ⊢ ((𝑥 ∈ TopBases ∧ 𝑥 ≼ ω) → 𝑥 ≼ ω) | |
4 | nnenom 13942 | . . . . . . . . . 10 ⊢ ℕ ≈ ω | |
5 | 4 | ensymi 8996 | . . . . . . . . 9 ⊢ ω ≈ ℕ |
6 | domentr 9005 | . . . . . . . . 9 ⊢ ((𝑥 ≼ ω ∧ ω ≈ ℕ) → 𝑥 ≼ ℕ) | |
7 | 3, 5, 6 | sylancl 585 | . . . . . . . 8 ⊢ ((𝑥 ∈ TopBases ∧ 𝑥 ≼ ω) → 𝑥 ≼ ℕ) |
8 | pwdom 9125 | . . . . . . . 8 ⊢ (𝑥 ≼ ℕ → 𝒫 𝑥 ≼ 𝒫 ℕ) | |
9 | 7, 8 | syl 17 | . . . . . . 7 ⊢ ((𝑥 ∈ TopBases ∧ 𝑥 ≼ ω) → 𝒫 𝑥 ≼ 𝒫 ℕ) |
10 | rpnnen 16167 | . . . . . . . 8 ⊢ ℝ ≈ 𝒫 ℕ | |
11 | 10 | ensymi 8996 | . . . . . . 7 ⊢ 𝒫 ℕ ≈ ℝ |
12 | domentr 9005 | . . . . . . 7 ⊢ ((𝒫 𝑥 ≼ 𝒫 ℕ ∧ 𝒫 ℕ ≈ ℝ) → 𝒫 𝑥 ≼ ℝ) | |
13 | 9, 11, 12 | sylancl 585 | . . . . . 6 ⊢ ((𝑥 ∈ TopBases ∧ 𝑥 ≼ ω) → 𝒫 𝑥 ≼ ℝ) |
14 | domtr 8999 | . . . . . 6 ⊢ (((topGen‘𝑥) ≼ 𝒫 𝑥 ∧ 𝒫 𝑥 ≼ ℝ) → (topGen‘𝑥) ≼ ℝ) | |
15 | 2, 13, 14 | syl2an2r 682 | . . . . 5 ⊢ ((𝑥 ∈ TopBases ∧ 𝑥 ≼ ω) → (topGen‘𝑥) ≼ ℝ) |
16 | breq1 5141 | . . . . 5 ⊢ ((topGen‘𝑥) = 𝐽 → ((topGen‘𝑥) ≼ ℝ ↔ 𝐽 ≼ ℝ)) | |
17 | 15, 16 | syl5ibcom 244 | . . . 4 ⊢ ((𝑥 ∈ TopBases ∧ 𝑥 ≼ ω) → ((topGen‘𝑥) = 𝐽 → 𝐽 ≼ ℝ)) |
18 | 17 | expimpd 453 | . . 3 ⊢ (𝑥 ∈ TopBases → ((𝑥 ≼ ω ∧ (topGen‘𝑥) = 𝐽) → 𝐽 ≼ ℝ)) |
19 | 18 | rexlimiv 3140 | . 2 ⊢ (∃𝑥 ∈ TopBases (𝑥 ≼ ω ∧ (topGen‘𝑥) = 𝐽) → 𝐽 ≼ ℝ) |
20 | 1, 19 | sylbi 216 | 1 ⊢ (𝐽 ∈ 2ndω → 𝐽 ≼ ℝ) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 395 = wceq 1533 ∈ wcel 2098 ∃wrex 3062 𝒫 cpw 4594 class class class wbr 5138 ‘cfv 6533 ωcom 7848 ≈ cen 8932 ≼ cdom 8933 ℝcr 11105 ℕcn 12209 topGenctg 17382 TopBasesctb 22770 2ndωc2ndc 23264 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1789 ax-4 1803 ax-5 1905 ax-6 1963 ax-7 2003 ax-8 2100 ax-9 2108 ax-10 2129 ax-11 2146 ax-12 2163 ax-ext 2695 ax-rep 5275 ax-sep 5289 ax-nul 5296 ax-pow 5353 ax-pr 5417 ax-un 7718 ax-inf2 9632 ax-cnex 11162 ax-resscn 11163 ax-1cn 11164 ax-icn 11165 ax-addcl 11166 ax-addrcl 11167 ax-mulcl 11168 ax-mulrcl 11169 ax-mulcom 11170 ax-addass 11171 ax-mulass 11172 ax-distr 11173 ax-i2m1 11174 ax-1ne0 11175 ax-1rid 11176 ax-rnegex 11177 ax-rrecex 11178 ax-cnre 11179 ax-pre-lttri 11180 ax-pre-lttrn 11181 ax-pre-ltadd 11182 ax-pre-mulgt0 11183 ax-pre-sup 11184 |
This theorem depends on definitions: df-bi 206 df-an 396 df-or 845 df-3or 1085 df-3an 1086 df-tru 1536 df-fal 1546 df-ex 1774 df-nf 1778 df-sb 2060 df-mo 2526 df-eu 2555 df-clab 2702 df-cleq 2716 df-clel 2802 df-nfc 2877 df-ne 2933 df-nel 3039 df-ral 3054 df-rex 3063 df-rmo 3368 df-reu 3369 df-rab 3425 df-v 3468 df-sbc 3770 df-csb 3886 df-dif 3943 df-un 3945 df-in 3947 df-ss 3957 df-pss 3959 df-nul 4315 df-if 4521 df-pw 4596 df-sn 4621 df-pr 4623 df-op 4627 df-uni 4900 df-int 4941 df-iun 4989 df-br 5139 df-opab 5201 df-mpt 5222 df-tr 5256 df-id 5564 df-eprel 5570 df-po 5578 df-so 5579 df-fr 5621 df-se 5622 df-we 5623 df-xp 5672 df-rel 5673 df-cnv 5674 df-co 5675 df-dm 5676 df-rn 5677 df-res 5678 df-ima 5679 df-pred 6290 df-ord 6357 df-on 6358 df-lim 6359 df-suc 6360 df-iota 6485 df-fun 6535 df-fn 6536 df-f 6537 df-f1 6538 df-fo 6539 df-f1o 6540 df-fv 6541 df-isom 6542 df-riota 7357 df-ov 7404 df-oprab 7405 df-mpo 7406 df-om 7849 df-1st 7968 df-2nd 7969 df-frecs 8261 df-wrecs 8292 df-recs 8366 df-rdg 8405 df-1o 8461 df-2o 8462 df-oadd 8465 df-omul 8466 df-er 8699 df-map 8818 df-pm 8819 df-en 8936 df-dom 8937 df-sdom 8938 df-fin 8939 df-sup 9433 df-inf 9434 df-oi 9501 df-card 9930 df-acn 9933 df-pnf 11247 df-mnf 11248 df-xr 11249 df-ltxr 11250 df-le 11251 df-sub 11443 df-neg 11444 df-div 11869 df-nn 12210 df-2 12272 df-3 12273 df-n0 12470 df-z 12556 df-uz 12820 df-q 12930 df-rp 12972 df-ico 13327 df-icc 13328 df-fz 13482 df-fzo 13625 df-fl 13754 df-seq 13964 df-exp 14025 df-hash 14288 df-cj 15043 df-re 15044 df-im 15045 df-sqrt 15179 df-abs 15180 df-limsup 15412 df-clim 15429 df-rlim 15430 df-sum 15630 df-topgen 17388 df-2ndc 23266 |
This theorem is referenced by: (None) |
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