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Mirrors > Home > ILE Home > Th. List > algcvgb | GIF version |
Description: Two ways of expressing that πΆ is a countdown function for algorithm πΉ. The first is used in these theorems. The second states the condition more intuitively as a conjunction: if the countdown function's value is currently nonzero, it must decrease at the next step; if it has reached zero, it must remain zero at the next step. (Contributed by Paul Chapman, 31-Mar-2011.) |
Ref | Expression |
---|---|
algcvgb.1 | β’ πΉ:πβΆπ |
algcvgb.2 | β’ πΆ:πβΆβ0 |
Ref | Expression |
---|---|
algcvgb | β’ (π β π β (((πΆβ(πΉβπ)) β 0 β (πΆβ(πΉβπ)) < (πΆβπ)) β (((πΆβπ) β 0 β (πΆβ(πΉβπ)) < (πΆβπ)) β§ ((πΆβπ) = 0 β (πΆβ(πΉβπ)) = 0)))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | algcvgb.2 | . . 3 β’ πΆ:πβΆβ0 | |
2 | 1 | ffvelcdmi 5642 | . 2 β’ (π β π β (πΆβπ) β β0) |
3 | algcvgb.1 | . . . 4 β’ πΉ:πβΆπ | |
4 | 3 | ffvelcdmi 5642 | . . 3 β’ (π β π β (πΉβπ) β π) |
5 | 1 | ffvelcdmi 5642 | . . 3 β’ ((πΉβπ) β π β (πΆβ(πΉβπ)) β β0) |
6 | 4, 5 | syl 14 | . 2 β’ (π β π β (πΆβ(πΉβπ)) β β0) |
7 | algcvgblem 12015 | . 2 β’ (((πΆβπ) β β0 β§ (πΆβ(πΉβπ)) β β0) β (((πΆβ(πΉβπ)) β 0 β (πΆβ(πΉβπ)) < (πΆβπ)) β (((πΆβπ) β 0 β (πΆβ(πΉβπ)) < (πΆβπ)) β§ ((πΆβπ) = 0 β (πΆβ(πΉβπ)) = 0)))) | |
8 | 2, 6, 7 | syl2anc 411 | 1 β’ (π β π β (((πΆβ(πΉβπ)) β 0 β (πΆβ(πΉβπ)) < (πΆβπ)) β (((πΆβπ) β 0 β (πΆβ(πΉβπ)) < (πΆβπ)) β§ ((πΆβπ) = 0 β (πΆβ(πΉβπ)) = 0)))) |
Colors of variables: wff set class |
Syntax hints: β wi 4 β§ wa 104 β wb 105 = wceq 1353 β wcel 2146 β wne 2345 class class class wbr 3998 βΆwf 5204 βcfv 5208 0cc0 7786 < clt 7966 β0cn0 9147 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-in1 614 ax-in2 615 ax-io 709 ax-5 1445 ax-7 1446 ax-gen 1447 ax-ie1 1491 ax-ie2 1492 ax-8 1502 ax-10 1503 ax-11 1504 ax-i12 1505 ax-bndl 1507 ax-4 1508 ax-17 1524 ax-i9 1528 ax-ial 1532 ax-i5r 1533 ax-13 2148 ax-14 2149 ax-ext 2157 ax-sep 4116 ax-pow 4169 ax-pr 4203 ax-un 4427 ax-setind 4530 ax-cnex 7877 ax-resscn 7878 ax-1cn 7879 ax-1re 7880 ax-icn 7881 ax-addcl 7882 ax-addrcl 7883 ax-mulcl 7884 ax-addcom 7886 ax-addass 7888 ax-distr 7890 ax-i2m1 7891 ax-0lt1 7892 ax-0id 7894 ax-rnegex 7895 ax-cnre 7897 ax-pre-ltirr 7898 ax-pre-ltwlin 7899 ax-pre-lttrn 7900 ax-pre-apti 7901 ax-pre-ltadd 7902 |
This theorem depends on definitions: df-bi 117 df-stab 831 df-dc 835 df-3or 979 df-3an 980 df-tru 1356 df-fal 1359 df-nf 1459 df-sb 1761 df-eu 2027 df-mo 2028 df-clab 2162 df-cleq 2168 df-clel 2171 df-nfc 2306 df-ne 2346 df-nel 2441 df-ral 2458 df-rex 2459 df-reu 2460 df-rab 2462 df-v 2737 df-sbc 2961 df-dif 3129 df-un 3131 df-in 3133 df-ss 3140 df-pw 3574 df-sn 3595 df-pr 3596 df-op 3598 df-uni 3806 df-int 3841 df-br 3999 df-opab 4060 df-id 4287 df-xp 4626 df-rel 4627 df-cnv 4628 df-co 4629 df-dm 4630 df-rn 4631 df-iota 5170 df-fun 5210 df-fn 5211 df-f 5212 df-fv 5216 df-riota 5821 df-ov 5868 df-oprab 5869 df-mpo 5870 df-pnf 7968 df-mnf 7969 df-xr 7970 df-ltxr 7971 df-le 7972 df-sub 8104 df-neg 8105 df-inn 8891 df-n0 9148 df-z 9225 |
This theorem is referenced by: algcvga 12017 |
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