zdceq - Intuitionistic Logic Explorer

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Theorem zdceq 9328

Description: Equality of integers is decidable. (Contributed by Jim Kingdon, 14-Mar-2020.)

**Assertion**
Ref	Expression
zdceq	⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → DECID 𝐴 = 𝐵)

**Proof of Theorem zdceq**
Step	Hyp	Ref	Expression
1		ztri3or 9296	. 2 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → (𝐴 < 𝐵 ∨ 𝐴 = 𝐵 ∨ 𝐵 < 𝐴))
2		zre 9257	. . . 4 ⊢ (𝐴 ∈ ℤ → 𝐴 ∈ ℝ)
3		ltne 8042	. . . . . . . 8 ⊢ ((𝐴 ∈ ℝ ∧ 𝐴 < 𝐵) → 𝐵 ≠ 𝐴)
4	3	necomd 2433	. . . . . . 7 ⊢ ((𝐴 ∈ ℝ ∧ 𝐴 < 𝐵) → 𝐴 ≠ 𝐵)
5		olc 711	. . . . . . . 8 ⊢ (𝐴 ≠ 𝐵 → (𝐴 = 𝐵 ∨ 𝐴 ≠ 𝐵))
6		dcne 2358	. . . . . . . 8 ⊢ (DECID 𝐴 = 𝐵 ↔ (𝐴 = 𝐵 ∨ 𝐴 ≠ 𝐵))
7	5, 6	sylibr 134	. . . . . . 7 ⊢ (𝐴 ≠ 𝐵 → DECID 𝐴 = 𝐵)
8	4, 7	syl 14	. . . . . 6 ⊢ ((𝐴 ∈ ℝ ∧ 𝐴 < 𝐵) → DECID 𝐴 = 𝐵)
9	8	ex 115	. . . . 5 ⊢ (𝐴 ∈ ℝ → (𝐴 < 𝐵 → DECID 𝐴 = 𝐵))
10	9	adantr 276	. . . 4 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℤ) → (𝐴 < 𝐵 → DECID 𝐴 = 𝐵))
11	2, 10	sylan 283	. . 3 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → (𝐴 < 𝐵 → DECID 𝐴 = 𝐵))
12		orc 712	. . . . 5 ⊢ (𝐴 = 𝐵 → (𝐴 = 𝐵 ∨ 𝐴 ≠ 𝐵))
13	12, 6	sylibr 134	. . . 4 ⊢ (𝐴 = 𝐵 → DECID 𝐴 = 𝐵)
14	13	a1i 9	. . 3 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → (𝐴 = 𝐵 → DECID 𝐴 = 𝐵))
15		zre 9257	. . . . 5 ⊢ (𝐵 ∈ ℤ → 𝐵 ∈ ℝ)
16		ltne 8042	. . . . . . 7 ⊢ ((𝐵 ∈ ℝ ∧ 𝐵 < 𝐴) → 𝐴 ≠ 𝐵)
17	16, 7	syl 14	. . . . . 6 ⊢ ((𝐵 ∈ ℝ ∧ 𝐵 < 𝐴) → DECID 𝐴 = 𝐵)
18	17	ex 115	. . . . 5 ⊢ (𝐵 ∈ ℝ → (𝐵 < 𝐴 → DECID 𝐴 = 𝐵))
19	15, 18	syl 14	. . . 4 ⊢ (𝐵 ∈ ℤ → (𝐵 < 𝐴 → DECID 𝐴 = 𝐵))
20	19	adantl 277	. . 3 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → (𝐵 < 𝐴 → DECID 𝐴 = 𝐵))
21	11, 14, 20	3jaod 1304	. 2 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → ((𝐴 < 𝐵 ∨ 𝐴 = 𝐵 ∨ 𝐵 < 𝐴) → DECID 𝐴 = 𝐵))
22	1, 21	mpd 13	1 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → DECID 𝐴 = 𝐵)

Colors of variables: wff set class

Syntax hints: → wi 4 ∧ wa 104 ∨ wo 708 DECID wdc 834 ∨ w3o 977 = wceq 1353 ∈ wcel 2148 ≠ wne 2347 class class class wbr 4004 ℝcr 7810 < clt 7992 ℤcz 9253

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 1447 ax-7 1448 ax-gen 1449 ax-ie1 1493 ax-ie2 1494 ax-8 1504 ax-10 1505 ax-11 1506 ax-i12 1507 ax-bndl 1509 ax-4 1510 ax-17 1526 ax-i9 1530 ax-ial 1534 ax-i5r 1535 ax-13 2150 ax-14 2151 ax-ext 2159 ax-sep 4122 ax-pow 4175 ax-pr 4210 ax-un 4434 ax-setind 4537 ax-cnex 7902 ax-resscn 7903 ax-1cn 7904 ax-1re 7905 ax-icn 7906 ax-addcl 7907 ax-addrcl 7908 ax-mulcl 7909 ax-addcom 7911 ax-addass 7913 ax-distr 7915 ax-i2m1 7916 ax-0lt1 7917 ax-0id 7919 ax-rnegex 7920 ax-cnre 7922 ax-pre-ltirr 7923 ax-pre-ltwlin 7924 ax-pre-lttrn 7925 ax-pre-ltadd 7927

This theorem depends on definitions: df-bi 117 df-dc 835 df-3or 979 df-3an 980 df-tru 1356 df-fal 1359 df-nf 1461 df-sb 1763 df-eu 2029 df-mo 2030 df-clab 2164 df-cleq 2170 df-clel 2173 df-nfc 2308 df-ne 2348 df-nel 2443 df-ral 2460 df-rex 2461 df-reu 2462 df-rab 2464 df-v 2740 df-sbc 2964 df-dif 3132 df-un 3134 df-in 3136 df-ss 3143 df-pw 3578 df-sn 3599 df-pr 3600 df-op 3602 df-uni 3811 df-int 3846 df-br 4005 df-opab 4066 df-id 4294 df-xp 4633 df-rel 4634 df-cnv 4635 df-co 4636 df-dm 4637 df-iota 5179 df-fun 5219 df-fv 5225 df-riota 5831 df-ov 5878 df-oprab 5879 df-mpo 5880 df-pnf 7994 df-mnf 7995 df-xr 7996 df-ltxr 7997 df-le 7998 df-sub 8130 df-neg 8131 df-inn 8920 df-n0 9177 df-z 9254

This theorem is referenced by: nn0n0n1ge2b 9332 nn0lt2 9334 prime 9352 elnn1uz2 9607 iseqf1olemqcl 10486 iseqf1olemnab 10488 iseqf1olemab 10489 seq3f1olemstep 10501 exp3val 10522 hashfzp1 10804 fprod1p 11607 dvdsdc 11805 zdvdsdc 11819 dvdsabseq 11853 alzdvds 11860 fzo0dvdseq 11863 gcdmndc 11945 gcdsupex 11958 gcdsupcl 11959 gcd0id 11980 gcdaddm 11985 dfgcd2 12015 gcdmultiplez 12022 dvdssq 12032 nn0seqcvgd 12041 algcvgblem 12049 eucalgval2 12053 lcmmndc 12062 lcmdvds 12079 lcmid 12080 mulgcddvds 12094 cncongr2 12104 isprm3 12118 isprm4 12119 prm2orodd 12126 rpexp 12153 phivalfi 12212 phiprmpw 12222 phimullem 12225 eulerthlemfi 12228 hashgcdeq 12239 phisum 12240 pcxnn0cl 12310 pcge0 12312 pcdvdsb 12319 pcneg 12324 pcdvdstr 12326 pcgcd1 12327 pc2dvds 12329 pcz 12331 pcprmpw2 12332 pcmpt 12341 ennnfonelemim 12425 unbendc 12455 strsetsid 12495 mulgval 12986 mulgfng 12987 subgmulg 13048 lgsval 14408 lgsfvalg 14409 lgsfcl2 14410 lgscllem 14411 lgsval2lem 14414 lgsneg1 14429 lgsdir2 14437 lgsdirprm 14438 lgsdir 14439 lgsne0 14442 lgsprme0 14446 lgsdirnn0 14451 lgsdinn0 14452 2sqlem9 14474 nninffeq 14772 nconstwlpolem 14815

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