Theorem infxrunb3rnmpt 44138

Description: The infimum of an unbounded-below set of extended reals is minus infinity. (Contributed by Glauco Siliprandi, 23-Oct-2021.)

Hypotheses

Ref	Expression
infxrunb3rnmpt.1	⊢ Ⅎ𝑥𝜑
infxrunb3rnmpt.2	⊢ Ⅎ𝑦𝜑
infxrunb3rnmpt.3	⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → 𝐵 ∈ ℝ*)

Assertion

Ref	Expression
infxrunb3rnmpt	⊢ (𝜑 → (∀𝑦 ∈ ℝ ∃𝑥 ∈ 𝐴 𝐵 ≤ 𝑦 ↔ inf(ran (𝑥 ∈ 𝐴 ↦ 𝐵), ℝ*, < ) = -∞))

Distinct variable groups:   𝑥,𝐴,𝑦   𝑦,𝐵

Allowed substitution hints:   𝜑(𝑥,𝑦)   𝐵(𝑥)

Proof of Theorem infxrunb3rnmpt

Dummy variable 𝑧 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		infxrunb3rnmpt.2	. . 3 ⊢ Ⅎ𝑦𝜑
2		infxrunb3rnmpt.1	. . . . 5 ⊢ Ⅎ𝑥𝜑
3		nfmpt1 5257	. . . . . . 7 ⊢ Ⅎ𝑥(𝑥 ∈ 𝐴 ↦ 𝐵)
4	3	nfrn 5952	. . . . . 6 ⊢ Ⅎ𝑥ran (𝑥 ∈ 𝐴 ↦ 𝐵)
5		nfv 1918	. . . . . 6 ⊢ Ⅎ𝑥 𝑧 ≤ 𝑦
6	4, 5	nfrexw 3311	. . . . 5 ⊢ Ⅎ𝑥∃𝑧 ∈ ran (𝑥 ∈ 𝐴 ↦ 𝐵)𝑧 ≤ 𝑦
7		simpr 486	. . . . . . . . 9 ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → 𝑥 ∈ 𝐴)
8		infxrunb3rnmpt.3	. . . . . . . . 9 ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → 𝐵 ∈ ℝ*)
9		eqid 2733	. . . . . . . . . 10 ⊢ (𝑥 ∈ 𝐴 ↦ 𝐵) = (𝑥 ∈ 𝐴 ↦ 𝐵)
10	9	elrnmpt1 5958	. . . . . . . . 9 ⊢ ((𝑥 ∈ 𝐴 ∧ 𝐵 ∈ ℝ*) → 𝐵 ∈ ran (𝑥 ∈ 𝐴 ↦ 𝐵))
11	7, 8, 10	syl2anc 585	. . . . . . . 8 ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → 𝐵 ∈ ran (𝑥 ∈ 𝐴 ↦ 𝐵))
12	11	3adant3 1133	. . . . . . 7 ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴 ∧ 𝐵 ≤ 𝑦) → 𝐵 ∈ ran (𝑥 ∈ 𝐴 ↦ 𝐵))
13		simp3 1139	. . . . . . 7 ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴 ∧ 𝐵 ≤ 𝑦) → 𝐵 ≤ 𝑦)
14		breq1 5152	. . . . . . . 8 ⊢ (𝑧 = 𝐵 → (𝑧 ≤ 𝑦 ↔ 𝐵 ≤ 𝑦))
15	14	rspcev 3613	. . . . . . 7 ⊢ ((𝐵 ∈ ran (𝑥 ∈ 𝐴 ↦ 𝐵) ∧ 𝐵 ≤ 𝑦) → ∃𝑧 ∈ ran (𝑥 ∈ 𝐴 ↦ 𝐵)𝑧 ≤ 𝑦)
16	12, 13, 15	syl2anc 585	. . . . . 6 ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴 ∧ 𝐵 ≤ 𝑦) → ∃𝑧 ∈ ran (𝑥 ∈ 𝐴 ↦ 𝐵)𝑧 ≤ 𝑦)
17	16	3exp 1120	. . . . 5 ⊢ (𝜑 → (𝑥 ∈ 𝐴 → (𝐵 ≤ 𝑦 → ∃𝑧 ∈ ran (𝑥 ∈ 𝐴 ↦ 𝐵)𝑧 ≤ 𝑦)))
18	2, 6, 17	rexlimd 3264	. . . 4 ⊢ (𝜑 → (∃𝑥 ∈ 𝐴 𝐵 ≤ 𝑦 → ∃𝑧 ∈ ran (𝑥 ∈ 𝐴 ↦ 𝐵)𝑧 ≤ 𝑦))
19		nfv 1918	. . . . . 6 ⊢ Ⅎ𝑧∃𝑥 ∈ 𝐴 𝐵 ≤ 𝑦
20		vex 3479	. . . . . . . . 9 ⊢ 𝑧 ∈ V
21	9	elrnmpt 5956	. . . . . . . . 9 ⊢ (𝑧 ∈ V → (𝑧 ∈ ran (𝑥 ∈ 𝐴 ↦ 𝐵) ↔ ∃𝑥 ∈ 𝐴 𝑧 = 𝐵))
22	20, 21	ax-mp 5	. . . . . . . 8 ⊢ (𝑧 ∈ ran (𝑥 ∈ 𝐴 ↦ 𝐵) ↔ ∃𝑥 ∈ 𝐴 𝑧 = 𝐵)
23	22	biimpi 215	. . . . . . 7 ⊢ (𝑧 ∈ ran (𝑥 ∈ 𝐴 ↦ 𝐵) → ∃𝑥 ∈ 𝐴 𝑧 = 𝐵)
24	14	biimpcd 248	. . . . . . . . . 10 ⊢ (𝑧 ≤ 𝑦 → (𝑧 = 𝐵 → 𝐵 ≤ 𝑦))
25	24	a1d 25	. . . . . . . . 9 ⊢ (𝑧 ≤ 𝑦 → (𝑥 ∈ 𝐴 → (𝑧 = 𝐵 → 𝐵 ≤ 𝑦)))
26	5, 25	reximdai 3259	. . . . . . . 8 ⊢ (𝑧 ≤ 𝑦 → (∃𝑥 ∈ 𝐴 𝑧 = 𝐵 → ∃𝑥 ∈ 𝐴 𝐵 ≤ 𝑦))
27	26	com12 32	. . . . . . 7 ⊢ (∃𝑥 ∈ 𝐴 𝑧 = 𝐵 → (𝑧 ≤ 𝑦 → ∃𝑥 ∈ 𝐴 𝐵 ≤ 𝑦))
28	23, 27	syl 17	. . . . . 6 ⊢ (𝑧 ∈ ran (𝑥 ∈ 𝐴 ↦ 𝐵) → (𝑧 ≤ 𝑦 → ∃𝑥 ∈ 𝐴 𝐵 ≤ 𝑦))
29	19, 28	rexlimi 3257	. . . . 5 ⊢ (∃𝑧 ∈ ran (𝑥 ∈ 𝐴 ↦ 𝐵)𝑧 ≤ 𝑦 → ∃𝑥 ∈ 𝐴 𝐵 ≤ 𝑦)
30	29	a1i 11	. . . 4 ⊢ (𝜑 → (∃𝑧 ∈ ran (𝑥 ∈ 𝐴 ↦ 𝐵)𝑧 ≤ 𝑦 → ∃𝑥 ∈ 𝐴 𝐵 ≤ 𝑦))
31	18, 30	impbid 211	. . 3 ⊢ (𝜑 → (∃𝑥 ∈ 𝐴 𝐵 ≤ 𝑦 ↔ ∃𝑧 ∈ ran (𝑥 ∈ 𝐴 ↦ 𝐵)𝑧 ≤ 𝑦))
32	1, 31	ralbid 3271	. 2 ⊢ (𝜑 → (∀𝑦 ∈ ℝ ∃𝑥 ∈ 𝐴 𝐵 ≤ 𝑦 ↔ ∀𝑦 ∈ ℝ ∃𝑧 ∈ ran (𝑥 ∈ 𝐴 ↦ 𝐵)𝑧 ≤ 𝑦))
33	2, 9, 8	rnmptssd 43895	. . 3 ⊢ (𝜑 → ran (𝑥 ∈ 𝐴 ↦ 𝐵) ⊆ ℝ*)
34		infxrunb3 44134	. . 3 ⊢ (ran (𝑥 ∈ 𝐴 ↦ 𝐵) ⊆ ℝ* → (∀𝑦 ∈ ℝ ∃𝑧 ∈ ran (𝑥 ∈ 𝐴 ↦ 𝐵)𝑧 ≤ 𝑦 ↔ inf(ran (𝑥 ∈ 𝐴 ↦ 𝐵), ℝ*, < ) = -∞))
35	33, 34	syl 17	. 2 ⊢ (𝜑 → (∀𝑦 ∈ ℝ ∃𝑧 ∈ ran (𝑥 ∈ 𝐴 ↦ 𝐵)𝑧 ≤ 𝑦 ↔ inf(ran (𝑥 ∈ 𝐴 ↦ 𝐵), ℝ*, < ) = -∞))
36	32, 35	bitrd 279	1 ⊢ (𝜑 → (∀𝑦 ∈ ℝ ∃𝑥 ∈ 𝐴 𝐵 ≤ 𝑦 ↔ inf(ran (𝑥 ∈ 𝐴 ↦ 𝐵), ℝ*, < ) = -∞))

Syntax hints:   → wi 4   ↔ wb 205   ∧ wa 397   ∧ w3a 1088   = wceq 1542  Ⅎwnf 1786   ∈ wcel 2107  ∀wral 3062  ∃wrex 3071  Vcvv 3475   ⊆ wss 3949   class class class wbr 5149   ↦ cmpt 5232  ran crn 5678  infcinf 9436  ℝcr 11109  -∞cmnf 11246  ℝ^*cxr 11247   < clt 11248   ≤ cle 11249

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1798  ax-4 1812  ax-5 1914  ax-6 1972  ax-7 2012  ax-8 2109  ax-9 2117  ax-10 2138  ax-11 2155  ax-12 2172  ax-ext 2704  ax-sep 5300  ax-nul 5307  ax-pow 5364  ax-pr 5428  ax-un 7725  ax-cnex 11166  ax-resscn 11167  ax-1cn 11168  ax-icn 11169  ax-addcl 11170  ax-addrcl 11171  ax-mulcl 11172  ax-mulrcl 11173  ax-mulcom 11174  ax-addass 11175  ax-mulass 11176  ax-distr 11177  ax-i2m1 11178  ax-1ne0 11179  ax-1rid 11180  ax-rnegex 11181  ax-rrecex 11182  ax-cnre 11183  ax-pre-lttri 11184  ax-pre-lttrn 11185  ax-pre-ltadd 11186  ax-pre-mulgt0 11187  ax-pre-sup 11188

This theorem depends on definitions:  df-bi 206  df-an 398  df-or 847  df-3or 1089  df-3an 1090  df-tru 1545  df-fal 1555  df-ex 1783  df-nf 1787  df-sb 2069  df-mo 2535  df-eu 2564  df-clab 2711  df-cleq 2725  df-clel 2811  df-nfc 2886  df-ne 2942  df-nel 3048  df-ral 3063  df-rex 3072  df-rmo 3377  df-reu 3378  df-rab 3434  df-v 3477  df-sbc 3779  df-csb 3895  df-dif 3952  df-un 3954  df-in 3956  df-ss 3966  df-nul 4324  df-if 4530  df-pw 4605  df-sn 4630  df-pr 4632  df-op 4636  df-uni 4910  df-br 5150  df-opab 5212  df-mpt 5233  df-id 5575  df-po 5589  df-so 5590  df-xp 5683  df-rel 5684  df-cnv 5685  df-co 5686  df-dm 5687  df-rn 5688  df-res 5689  df-ima 5690  df-iota 6496  df-fun 6546  df-fn 6547  df-f 6548  df-f1 6549  df-fo 6550  df-f1o 6551  df-fv 6552  df-riota 7365  df-ov 7412  df-oprab 7413  df-mpo 7414  df-er 8703  df-en 8940  df-dom 8941  df-sdom 8942  df-sup 9437  df-inf 9438  df-pnf 11250  df-mnf 11251  df-xr 11252  df-ltxr 11253  df-le 11254  df-sub 11446  df-neg 11447

This theorem is referenced by:  limsupmnflem  44436