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Mirrors > Home > MPE Home > Th. List > expnngt1b | Structured version Visualization version GIF version |
Description: An integer power with an integer base greater than 1 is greater than 1 iff the exponent is positive. (Contributed by AV, 28-Dec-2022.) |
Ref | Expression |
---|---|
expnngt1b | ⊢ ((𝐴 ∈ (ℤ≥‘2) ∧ 𝐵 ∈ ℤ) → (1 < (𝐴↑𝐵) ↔ 𝐵 ∈ ℕ)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | eluz2nn 12282 | . . . . 5 ⊢ (𝐴 ∈ (ℤ≥‘2) → 𝐴 ∈ ℕ) | |
2 | 1 | adantr 483 | . . . 4 ⊢ ((𝐴 ∈ (ℤ≥‘2) ∧ 𝐵 ∈ ℤ) → 𝐴 ∈ ℕ) |
3 | 2 | adantr 483 | . . 3 ⊢ (((𝐴 ∈ (ℤ≥‘2) ∧ 𝐵 ∈ ℤ) ∧ 1 < (𝐴↑𝐵)) → 𝐴 ∈ ℕ) |
4 | simplr 767 | . . 3 ⊢ (((𝐴 ∈ (ℤ≥‘2) ∧ 𝐵 ∈ ℤ) ∧ 1 < (𝐴↑𝐵)) → 𝐵 ∈ ℤ) | |
5 | simpr 487 | . . 3 ⊢ (((𝐴 ∈ (ℤ≥‘2) ∧ 𝐵 ∈ ℤ) ∧ 1 < (𝐴↑𝐵)) → 1 < (𝐴↑𝐵)) | |
6 | expnngt1 13600 | . . 3 ⊢ ((𝐴 ∈ ℕ ∧ 𝐵 ∈ ℤ ∧ 1 < (𝐴↑𝐵)) → 𝐵 ∈ ℕ) | |
7 | 3, 4, 5, 6 | syl3anc 1366 | . 2 ⊢ (((𝐴 ∈ (ℤ≥‘2) ∧ 𝐵 ∈ ℤ) ∧ 1 < (𝐴↑𝐵)) → 𝐵 ∈ ℕ) |
8 | 2 | nnred 11650 | . . . 4 ⊢ ((𝐴 ∈ (ℤ≥‘2) ∧ 𝐵 ∈ ℤ) → 𝐴 ∈ ℝ) |
9 | 8 | adantr 483 | . . 3 ⊢ (((𝐴 ∈ (ℤ≥‘2) ∧ 𝐵 ∈ ℤ) ∧ 𝐵 ∈ ℕ) → 𝐴 ∈ ℝ) |
10 | simpr 487 | . . 3 ⊢ (((𝐴 ∈ (ℤ≥‘2) ∧ 𝐵 ∈ ℤ) ∧ 𝐵 ∈ ℕ) → 𝐵 ∈ ℕ) | |
11 | eluz2gt1 12318 | . . . . 5 ⊢ (𝐴 ∈ (ℤ≥‘2) → 1 < 𝐴) | |
12 | 11 | adantr 483 | . . . 4 ⊢ ((𝐴 ∈ (ℤ≥‘2) ∧ 𝐵 ∈ ℤ) → 1 < 𝐴) |
13 | 12 | adantr 483 | . . 3 ⊢ (((𝐴 ∈ (ℤ≥‘2) ∧ 𝐵 ∈ ℤ) ∧ 𝐵 ∈ ℕ) → 1 < 𝐴) |
14 | expgt1 13465 | . . 3 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℕ ∧ 1 < 𝐴) → 1 < (𝐴↑𝐵)) | |
15 | 9, 10, 13, 14 | syl3anc 1366 | . 2 ⊢ (((𝐴 ∈ (ℤ≥‘2) ∧ 𝐵 ∈ ℤ) ∧ 𝐵 ∈ ℕ) → 1 < (𝐴↑𝐵)) |
16 | 7, 15 | impbida 799 | 1 ⊢ ((𝐴 ∈ (ℤ≥‘2) ∧ 𝐵 ∈ ℤ) → (1 < (𝐴↑𝐵) ↔ 𝐵 ∈ ℕ)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 208 ∧ wa 398 ∈ wcel 2113 class class class wbr 5063 ‘cfv 6352 (class class class)co 7153 ℝcr 10533 1c1 10535 < clt 10672 ℕcn 11635 2c2 11690 ℤcz 11979 ℤ≥cuz 12241 ↑cexp 13427 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1795 ax-4 1809 ax-5 1910 ax-6 1969 ax-7 2014 ax-8 2115 ax-9 2123 ax-10 2144 ax-11 2160 ax-12 2176 ax-ext 2792 ax-sep 5200 ax-nul 5207 ax-pow 5263 ax-pr 5327 ax-un 7458 ax-cnex 10590 ax-resscn 10591 ax-1cn 10592 ax-icn 10593 ax-addcl 10594 ax-addrcl 10595 ax-mulcl 10596 ax-mulrcl 10597 ax-mulcom 10598 ax-addass 10599 ax-mulass 10600 ax-distr 10601 ax-i2m1 10602 ax-1ne0 10603 ax-1rid 10604 ax-rnegex 10605 ax-rrecex 10606 ax-cnre 10607 ax-pre-lttri 10608 ax-pre-lttrn 10609 ax-pre-ltadd 10610 ax-pre-mulgt0 10611 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-3or 1083 df-3an 1084 df-tru 1539 df-ex 1780 df-nf 1784 df-sb 2069 df-mo 2621 df-eu 2653 df-clab 2799 df-cleq 2813 df-clel 2892 df-nfc 2962 df-ne 3016 df-nel 3123 df-ral 3142 df-rex 3143 df-reu 3144 df-rmo 3145 df-rab 3146 df-v 3495 df-sbc 3771 df-csb 3881 df-dif 3936 df-un 3938 df-in 3940 df-ss 3949 df-pss 3951 df-nul 4289 df-if 4465 df-pw 4538 df-sn 4565 df-pr 4567 df-tp 4569 df-op 4571 df-uni 4836 df-iun 4918 df-br 5064 df-opab 5126 df-mpt 5144 df-tr 5170 df-id 5457 df-eprel 5462 df-po 5471 df-so 5472 df-fr 5511 df-we 5513 df-xp 5558 df-rel 5559 df-cnv 5560 df-co 5561 df-dm 5562 df-rn 5563 df-res 5564 df-ima 5565 df-pred 6145 df-ord 6191 df-on 6192 df-lim 6193 df-suc 6194 df-iota 6311 df-fun 6354 df-fn 6355 df-f 6356 df-f1 6357 df-fo 6358 df-f1o 6359 df-fv 6360 df-riota 7111 df-ov 7156 df-oprab 7157 df-mpo 7158 df-om 7578 df-2nd 7687 df-wrecs 7944 df-recs 8005 df-rdg 8043 df-er 8286 df-en 8507 df-dom 8508 df-sdom 8509 df-pnf 10674 df-mnf 10675 df-xr 10676 df-ltxr 10677 df-le 10678 df-sub 10869 df-neg 10870 df-div 11295 df-nn 11636 df-2 11698 df-n0 11896 df-z 11980 df-uz 12242 df-rp 12388 df-seq 13368 df-exp 13428 |
This theorem is referenced by: (None) |
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