Theorem nnminle 12551

Description: The infimum of a decidable subset of the natural numbers is less than an element of the set. The infimum is also a minimum as shown at nnmindc 12550. (Contributed by Jim Kingdon, 26-Sep-2024.)

Assertion

Ref	Expression
nnminle	⊢ ((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴 ∧ 𝐵 ∈ 𝐴) → inf(𝐴, ℝ, < ) ≤ 𝐵)

Distinct variable group:   𝑥,𝐴

Allowed substitution hint:   𝐵(𝑥)

Proof of Theorem nnminle

Dummy variable 𝑛 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		dfss5 3409	. . . . . 6 ⊢ (𝐴 ⊆ ℕ ↔ 𝐴 = (ℕ ∩ 𝐴))
2	1	biimpi 120	. . . . 5 ⊢ (𝐴 ⊆ ℕ → 𝐴 = (ℕ ∩ 𝐴))
3		nnuz 9754	. . . . . . 7 ⊢ ℕ = (ℤ≥‘1)
4	3	ineq1i 3401	. . . . . 6 ⊢ (ℕ ∩ 𝐴) = ((ℤ≥‘1) ∩ 𝐴)
5		dfin5 3204	. . . . . 6 ⊢ ((ℤ≥‘1) ∩ 𝐴) = {𝑛 ∈ (ℤ≥‘1) ∣ 𝑛 ∈ 𝐴}
6	4, 5	eqtri 2250	. . . . 5 ⊢ (ℕ ∩ 𝐴) = {𝑛 ∈ (ℤ≥‘1) ∣ 𝑛 ∈ 𝐴}
7	2, 6	eqtrdi 2278	. . . 4 ⊢ (𝐴 ⊆ ℕ → 𝐴 = {𝑛 ∈ (ℤ≥‘1) ∣ 𝑛 ∈ 𝐴})
8	7	3ad2ant1 1042	. . 3 ⊢ ((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴 ∧ 𝐵 ∈ 𝐴) → 𝐴 = {𝑛 ∈ (ℤ≥‘1) ∣ 𝑛 ∈ 𝐴})
9	8	infeq1d 7175	. 2 ⊢ ((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴 ∧ 𝐵 ∈ 𝐴) → inf(𝐴, ℝ, < ) = inf({𝑛 ∈ (ℤ≥‘1) ∣ 𝑛 ∈ 𝐴}, ℝ, < ))
10		1zzd 9469	. . 3 ⊢ ((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴 ∧ 𝐵 ∈ 𝐴) → 1 ∈ ℤ)
11		eqid 2229	. . 3 ⊢ {𝑛 ∈ (ℤ≥‘1) ∣ 𝑛 ∈ 𝐴} = {𝑛 ∈ (ℤ≥‘1) ∣ 𝑛 ∈ 𝐴}
12		simp3 1023	. . . 4 ⊢ ((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴 ∧ 𝐵 ∈ 𝐴) → 𝐵 ∈ 𝐴)
13	12, 8	eleqtrd 2308	. . 3 ⊢ ((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴 ∧ 𝐵 ∈ 𝐴) → 𝐵 ∈ {𝑛 ∈ (ℤ≥‘1) ∣ 𝑛 ∈ 𝐴})
14		eleq1w 2290	. . . . 5 ⊢ (𝑥 = 𝑛 → (𝑥 ∈ 𝐴 ↔ 𝑛 ∈ 𝐴))
15	14	dcbid 843	. . . 4 ⊢ (𝑥 = 𝑛 → (DECID 𝑥 ∈ 𝐴 ↔ DECID 𝑛 ∈ 𝐴))
16		simpl2 1025	. . . 4 ⊢ (((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑛 ∈ (1...𝐵)) → ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴)
17		elfznn 10246	. . . . 5 ⊢ (𝑛 ∈ (1...𝐵) → 𝑛 ∈ ℕ)
18	17	adantl 277	. . . 4 ⊢ (((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑛 ∈ (1...𝐵)) → 𝑛 ∈ ℕ)
19	15, 16, 18	rspcdva 2912	. . 3 ⊢ (((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴 ∧ 𝐵 ∈ 𝐴) ∧ 𝑛 ∈ (1...𝐵)) → DECID 𝑛 ∈ 𝐴)
20	10, 11, 13, 19	infssuzledc 10449	. 2 ⊢ ((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴 ∧ 𝐵 ∈ 𝐴) → inf({𝑛 ∈ (ℤ≥‘1) ∣ 𝑛 ∈ 𝐴}, ℝ, < ) ≤ 𝐵)
21	9, 20	eqbrtrd 4104	1 ⊢ ((𝐴 ⊆ ℕ ∧ ∀𝑥 ∈ ℕ DECID 𝑥 ∈ 𝐴 ∧ 𝐵 ∈ 𝐴) → inf(𝐴, ℝ, < ) ≤ 𝐵)

Syntax hints:   → wi 4   ∧ wa 104  DECID wdc 839   ∧ w3a 1002   = wceq 1395   ∈ wcel 2200  ∀wral 2508  {crab 2512   ∩ cin 3196   ⊆ wss 3197   class class class wbr 4082  ‘cfv 5317  (class class class)co 6000  infcinf 7146  ℝcr 7994  1c1 7996   < clt 8177   ≤ cle 8178  ℕcn 9106  ℤ_≥cuz 9718  ...cfz 10200

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 617  ax-in2 618  ax-io 714  ax-5 1493  ax-7 1494  ax-gen 1495  ax-ie1 1539  ax-ie2 1540  ax-8 1550  ax-10 1551  ax-11 1552  ax-i12 1553  ax-bndl 1555  ax-4 1556  ax-17 1572  ax-i9 1576  ax-ial 1580  ax-i5r 1581  ax-13 2202  ax-14 2203  ax-ext 2211  ax-sep 4201  ax-pow 4257  ax-pr 4292  ax-un 4523  ax-setind 4628  ax-cnex 8086  ax-resscn 8087  ax-1cn 8088  ax-1re 8089  ax-icn 8090  ax-addcl 8091  ax-addrcl 8092  ax-mulcl 8093  ax-addcom 8095  ax-addass 8097  ax-distr 8099  ax-i2m1 8100  ax-0lt1 8101  ax-0id 8103  ax-rnegex 8104  ax-cnre 8106  ax-pre-ltirr 8107  ax-pre-ltwlin 8108  ax-pre-lttrn 8109  ax-pre-apti 8110  ax-pre-ltadd 8111

This theorem depends on definitions:  df-bi 117  df-dc 840  df-3or 1003  df-3an 1004  df-tru 1398  df-fal 1401  df-nf 1507  df-sb 1809  df-eu 2080  df-mo 2081  df-clab 2216  df-cleq 2222  df-clel 2225  df-nfc 2361  df-ne 2401  df-nel 2496  df-ral 2513  df-rex 2514  df-reu 2515  df-rmo 2516  df-rab 2517  df-v 2801  df-sbc 3029  df-csb 3125  df-dif 3199  df-un 3201  df-in 3203  df-ss 3210  df-pw 3651  df-sn 3672  df-pr 3673  df-op 3675  df-uni 3888  df-int 3923  df-iun 3966  df-br 4083  df-opab 4145  df-mpt 4146  df-id 4383  df-xp 4724  df-rel 4725  df-cnv 4726  df-co 4727  df-dm 4728  df-rn 4729  df-res 4730  df-ima 4731  df-iota 5277  df-fun 5319  df-fn 5320  df-f 5321  df-fv 5325  df-riota 5953  df-ov 6003  df-oprab 6004  df-mpo 6005  df-1st 6284  df-2nd 6285  df-sup 7147  df-inf 7148  df-pnf 8179  df-mnf 8180  df-xr 8181  df-ltxr 8182  df-le 8183  df-sub 8315  df-neg 8316  df-inn 9107  df-n0 9366  df-z 9443  df-uz 9719  df-fz 10201  df-fzo 10335

This theorem is referenced by:  nnwodc  12552