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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 16491 | . . 3 ⊢ Base = Slot 1 | |
2 | 1nn 11651 | . . 3 ⊢ 1 ∈ ℕ | |
3 | 1, 2 | ndxarg 16510 | . 2 ⊢ (Base‘ndx) = 1 |
4 | 3, 2 | eqeltri 2911 | 1 ⊢ (Base‘ndx) ∈ ℕ |
Colors of variables: wff setvar class |
Syntax hints: ∈ wcel 2114 ‘cfv 6357 1c1 10540 ℕcn 11640 ndxcnx 16482 Basecbs 16485 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1796 ax-4 1810 ax-5 1911 ax-6 1970 ax-7 2015 ax-8 2116 ax-9 2124 ax-10 2145 ax-11 2161 ax-12 2177 ax-ext 2795 ax-sep 5205 ax-nul 5212 ax-pow 5268 ax-pr 5332 ax-un 7463 ax-cnex 10595 ax-1cn 10597 ax-addcl 10599 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-3or 1084 df-3an 1085 df-tru 1540 df-ex 1781 df-nf 1785 df-sb 2070 df-mo 2622 df-eu 2654 df-clab 2802 df-cleq 2816 df-clel 2895 df-nfc 2965 df-ne 3019 df-ral 3145 df-rex 3146 df-reu 3147 df-rab 3149 df-v 3498 df-sbc 3775 df-csb 3886 df-dif 3941 df-un 3943 df-in 3945 df-ss 3954 df-pss 3956 df-nul 4294 df-if 4470 df-pw 4543 df-sn 4570 df-pr 4572 df-tp 4574 df-op 4576 df-uni 4841 df-iun 4923 df-br 5069 df-opab 5131 df-mpt 5149 df-tr 5175 df-id 5462 df-eprel 5467 df-po 5476 df-so 5477 df-fr 5516 df-we 5518 df-xp 5563 df-rel 5564 df-cnv 5565 df-co 5566 df-dm 5567 df-rn 5568 df-res 5569 df-ima 5570 df-pred 6150 df-ord 6196 df-on 6197 df-lim 6198 df-suc 6199 df-iota 6316 df-fun 6359 df-fn 6360 df-f 6361 df-f1 6362 df-fo 6363 df-f1o 6364 df-fv 6365 df-ov 7161 df-om 7583 df-wrecs 7949 df-recs 8010 df-rdg 8048 df-nn 11641 df-ndx 16488 df-slot 16489 df-base 16491 |
This theorem is referenced by: slotsbaseefdif 26782 structvtxvallem 26807 |
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