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Mirrors > Home > MPE Home > Th. List > basendxnn | Structured version Visualization version GIF version |
Description: The index value of the base set extractor is a positive integer. This property should be ensured for every concrete coding because otherwise it could not be used in an extensible structure (slots must be positive integers). (Contributed by AV, 23-Sep-2020.) |
Ref | Expression |
---|---|
basendxnn | ⊢ (Base‘ndx) ∈ ℕ |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-base 16235 | . . 3 ⊢ Base = Slot 1 | |
2 | 1nn 11370 | . . 3 ⊢ 1 ∈ ℕ | |
3 | 1, 2 | ndxarg 16254 | . 2 ⊢ (Base‘ndx) = 1 |
4 | 3, 2 | eqeltri 2902 | 1 ⊢ (Base‘ndx) ∈ ℕ |
Colors of variables: wff setvar class |
Syntax hints: ∈ wcel 2164 ‘cfv 6127 1c1 10260 ℕcn 11357 ndxcnx 16226 Basecbs 16229 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1894 ax-4 1908 ax-5 2009 ax-6 2075 ax-7 2112 ax-8 2166 ax-9 2173 ax-10 2192 ax-11 2207 ax-12 2220 ax-13 2389 ax-ext 2803 ax-sep 5007 ax-nul 5015 ax-pow 5067 ax-pr 5129 ax-un 7214 ax-cnex 10315 ax-1cn 10317 ax-addcl 10319 |
This theorem depends on definitions: df-bi 199 df-an 387 df-or 879 df-3or 1112 df-3an 1113 df-tru 1660 df-ex 1879 df-nf 1883 df-sb 2068 df-mo 2605 df-eu 2640 df-clab 2812 df-cleq 2818 df-clel 2821 df-nfc 2958 df-ne 3000 df-ral 3122 df-rex 3123 df-reu 3124 df-rab 3126 df-v 3416 df-sbc 3663 df-csb 3758 df-dif 3801 df-un 3803 df-in 3805 df-ss 3812 df-pss 3814 df-nul 4147 df-if 4309 df-pw 4382 df-sn 4400 df-pr 4402 df-tp 4404 df-op 4406 df-uni 4661 df-iun 4744 df-br 4876 df-opab 4938 df-mpt 4955 df-tr 4978 df-id 5252 df-eprel 5257 df-po 5265 df-so 5266 df-fr 5305 df-we 5307 df-xp 5352 df-rel 5353 df-cnv 5354 df-co 5355 df-dm 5356 df-rn 5357 df-res 5358 df-ima 5359 df-pred 5924 df-ord 5970 df-on 5971 df-lim 5972 df-suc 5973 df-iota 6090 df-fun 6129 df-fn 6130 df-f 6131 df-f1 6132 df-fo 6133 df-f1o 6134 df-fv 6135 df-ov 6913 df-om 7332 df-wrecs 7677 df-recs 7739 df-rdg 7777 df-nn 11358 df-ndx 16232 df-slot 16233 df-base 16235 |
This theorem is referenced by: slotsbaseefdif 26300 structvtxvallem 26325 |
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