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Mirrors > Home > MPE Home > Th. List > sgnrrp | Structured version Visualization version GIF version |
Description: The signum of a positive real is 1. (Contributed by David A. Wheeler, 18-May-2015.) |
Ref | Expression |
---|---|
sgnrrp | ⊢ (𝐴 ∈ ℝ+ → (sgn‘𝐴) = 1) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | rpxr 12978 | . 2 ⊢ (𝐴 ∈ ℝ+ → 𝐴 ∈ ℝ*) | |
2 | rpgt0 12981 | . 2 ⊢ (𝐴 ∈ ℝ+ → 0 < 𝐴) | |
3 | sgnp 15032 | . 2 ⊢ ((𝐴 ∈ ℝ* ∧ 0 < 𝐴) → (sgn‘𝐴) = 1) | |
4 | 1, 2, 3 | syl2anc 585 | 1 ⊢ (𝐴 ∈ ℝ+ → (sgn‘𝐴) = 1) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 = wceq 1542 ∈ wcel 2107 class class class wbr 5146 ‘cfv 6539 0cc0 11105 1c1 11106 ℝ*cxr 11242 < clt 11243 ℝ+crp 12969 sgncsgn 15028 |
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 5297 ax-nul 5304 ax-pow 5361 ax-pr 5425 ax-un 7719 ax-cnex 11161 ax-resscn 11162 ax-1cn 11163 ax-icn 11164 ax-addcl 11165 ax-addrcl 11166 ax-mulcl 11167 ax-i2m1 11173 ax-rnegex 11176 ax-cnre 11178 ax-pre-lttri 11179 ax-pre-lttrn 11180 |
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-rab 3434 df-v 3477 df-sbc 3776 df-csb 3892 df-dif 3949 df-un 3951 df-in 3953 df-ss 3963 df-nul 4321 df-if 4527 df-pw 4602 df-sn 4627 df-pr 4629 df-op 4633 df-uni 4907 df-br 5147 df-opab 5209 df-mpt 5230 df-id 5572 df-po 5586 df-so 5587 df-xp 5680 df-rel 5681 df-cnv 5682 df-co 5683 df-dm 5684 df-rn 5685 df-res 5686 df-ima 5687 df-iota 6491 df-fun 6541 df-fn 6542 df-f 6543 df-f1 6544 df-fo 6545 df-f1o 6546 df-fv 6547 df-ov 7406 df-er 8698 df-en 8935 df-dom 8936 df-sdom 8937 df-pnf 11245 df-mnf 11246 df-xr 11247 df-ltxr 11248 df-neg 11442 df-rp 12970 df-sgn 15029 |
This theorem is referenced by: (None) |
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