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Theorem zdcle 9671

Description: Integer ≤ is decidable. (Contributed by Jim Kingdon, 7-Apr-2020.)

**Assertion**
Ref	Expression
zdcle	⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → DECID 𝐴 ≤ 𝐵)

**Proof of Theorem zdcle**
Step	Hyp	Ref	Expression
1		ztri3or 9637	. 2 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → (𝐴 < 𝐵 ∨ 𝐴 = 𝐵 ∨ 𝐵 < 𝐴))
2		zre 9598	. . 3 ⊢ (𝐴 ∈ ℤ → 𝐴 ∈ ℝ)
3		zre 9598	. . 3 ⊢ (𝐵 ∈ ℤ → 𝐵 ∈ ℝ)
4		ltle 8377	. . . . 5 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (𝐴 < 𝐵 → 𝐴 ≤ 𝐵))
5		orc 720	. . . . . 6 ⊢ (𝐴 ≤ 𝐵 → (𝐴 ≤ 𝐵 ∨ ¬ 𝐴 ≤ 𝐵))
6		df-dc 843	. . . . . 6 ⊢ (DECID 𝐴 ≤ 𝐵 ↔ (𝐴 ≤ 𝐵 ∨ ¬ 𝐴 ≤ 𝐵))
7	5, 6	sylibr 134	. . . . 5 ⊢ (𝐴 ≤ 𝐵 → DECID 𝐴 ≤ 𝐵)
8	4, 7	syl6 33	. . . 4 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (𝐴 < 𝐵 → DECID 𝐴 ≤ 𝐵))
9		eqle 8381	. . . . . . 7 ⊢ ((𝐴 ∈ ℝ ∧ 𝐴 = 𝐵) → 𝐴 ≤ 𝐵)
10	9, 7	syl 14	. . . . . 6 ⊢ ((𝐴 ∈ ℝ ∧ 𝐴 = 𝐵) → DECID 𝐴 ≤ 𝐵)
11	10	ex 115	. . . . 5 ⊢ (𝐴 ∈ ℝ → (𝐴 = 𝐵 → DECID 𝐴 ≤ 𝐵))
12	11	adantr 276	. . . 4 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (𝐴 = 𝐵 → DECID 𝐴 ≤ 𝐵))
13		lenlt 8365	. . . . . . 7 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (𝐴 ≤ 𝐵 ↔ ¬ 𝐵 < 𝐴))
14	13	biimpd 144	. . . . . 6 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (𝐴 ≤ 𝐵 → ¬ 𝐵 < 𝐴))
15	14	con2d 629	. . . . 5 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (𝐵 < 𝐴 → ¬ 𝐴 ≤ 𝐵))
16		olc 719	. . . . . 6 ⊢ (¬ 𝐴 ≤ 𝐵 → (𝐴 ≤ 𝐵 ∨ ¬ 𝐴 ≤ 𝐵))
17	16, 6	sylibr 134	. . . . 5 ⊢ (¬ 𝐴 ≤ 𝐵 → DECID 𝐴 ≤ 𝐵)
18	15, 17	syl6 33	. . . 4 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (𝐵 < 𝐴 → DECID 𝐴 ≤ 𝐵))
19	8, 12, 18	3jaod 1341	. . 3 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → ((𝐴 < 𝐵 ∨ 𝐴 = 𝐵 ∨ 𝐵 < 𝐴) → DECID 𝐴 ≤ 𝐵))
20	2, 3, 19	syl2an 289	. 2 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → ((𝐴 < 𝐵 ∨ 𝐴 = 𝐵 ∨ 𝐵 < 𝐴) → DECID 𝐴 ≤ 𝐵))
21	1, 20	mpd 13	1 ⊢ ((𝐴 ∈ ℤ ∧ 𝐵 ∈ ℤ) → DECID 𝐴 ≤ 𝐵)

Colors of variables: wff set class

Syntax hints: ¬ wn 3 → wi 4 ∧ wa 104 ∨ wo 716 DECID wdc 842 ∨ w3o 1004 = wceq 1398 ∈ wcel 2205 class class class wbr 4114 ℝcr 8142 < clt 8324 ≤ cle 8325 ℤcz 9594

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 619 ax-in2 620 ax-io 717 ax-5 1496 ax-7 1497 ax-gen 1498 ax-ie1 1542 ax-ie2 1543 ax-8 1553 ax-10 1554 ax-11 1555 ax-i12 1556 ax-bndl 1558 ax-4 1559 ax-17 1575 ax-i9 1579 ax-ial 1583 ax-i5r 1584 ax-13 2207 ax-14 2208 ax-ext 2216 ax-sep 4233 ax-pow 4292 ax-pr 4327 ax-un 4559 ax-setind 4664 ax-cnex 8234 ax-resscn 8235 ax-1cn 8236 ax-1re 8237 ax-icn 8238 ax-addcl 8239 ax-addrcl 8240 ax-mulcl 8241 ax-addcom 8243 ax-addass 8245 ax-distr 8247 ax-i2m1 8248 ax-0lt1 8249 ax-0id 8251 ax-rnegex 8252 ax-cnre 8254 ax-pre-ltirr 8255 ax-pre-ltwlin 8256 ax-pre-lttrn 8257 ax-pre-ltadd 8259

This theorem depends on definitions: df-bi 117 df-dc 843 df-3or 1006 df-3an 1007 df-tru 1401 df-fal 1404 df-nf 1510 df-sb 1812 df-eu 2085 df-mo 2086 df-clab 2221 df-cleq 2227 df-clel 2230 df-nfc 2375 df-ne 2415 df-nel 2510 df-ral 2527 df-rex 2528 df-reu 2529 df-rab 2531 df-v 2817 df-sbc 3046 df-dif 3216 df-un 3218 df-in 3220 df-ss 3227 df-pw 3676 df-sn 3700 df-pr 3701 df-op 3703 df-uni 3920 df-int 3955 df-br 4115 df-opab 4177 df-id 4419 df-xp 4760 df-rel 4761 df-cnv 4762 df-co 4763 df-dm 4764 df-iota 5317 df-fun 5359 df-fv 5365 df-riota 6011 df-ov 6061 df-oprab 6062 df-mpo 6063 df-pnf 8326 df-mnf 8327 df-xr 8328 df-ltxr 8329 df-le 8330 df-sub 8462 df-neg 8463 df-inn 9255 df-n0 9514 df-z 9595

This theorem is referenced by: uzin 9905 xnn0dcle 10154 nelfzo 10508 exfzdc 10608 infssuzex 10615 infssfzcldc 10618 infssfzledc 10619 modfzo0difsn 10781 fzfig 10816 iseqf1olemjpcl 10894 iseqf1olemqpcl 10895 seq3f1oleml 10902 seq3f1o 10903 fser0const 10921 ccatsymb 11315 fzowrddc 11364 swrdnd 11376 swrdsbslen 11383 swrdspsleq 11384 pfxccat3 11451 swrdccat 11452 pfxccat3a 11455 swrdccat3blem 11456 swrdccat3b 11457 uzin2 11697 2zsupmax 11936 2zinfmin 11953 sumeq2 12069 summodclem2a 12092 fsum3 12098 fsumcl2lem 12109 fsumadd 12117 sumsnf 12120 fsummulc2 12159 explecnv 12216 prodeq2 12268 prodmodclem3 12286 prodmodclem2a 12287 fprodseq 12294 prod1dc 12297 fprodmul 12302 prodsnf 12303 pcdvdsb 13043 pcmpt2 13067 pcmptdvds 13068 pcprod 13069 pcfac 13073 1arithlem4 13089 ballotfilemfc0 13176 ballotfilemfcc 13177 ballotfilemodife 13184 ballotfilemsv 13197 ballotfilemsdom 13199 ballotfilemsf1o 13201 gsumgfsum 14106 plyaddlem1 15738 plyaddlem 15740

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