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Mirrors > Home > MPE Home > Th. List > areaval | Structured version Visualization version GIF version |
Description: The area of a measurable region is greater than or equal to zero. (Contributed by Mario Carneiro, 21-Jun-2015.) |
Ref | Expression |
---|---|
areaval | β’ (π β dom area β (areaβπ) = β«β(volβ(π β {π₯})) dπ₯) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | simpl 482 | . . . . 5 β’ ((π = π β§ π₯ β β) β π = π) | |
2 | 1 | imaeq1d 6058 | . . . 4 β’ ((π = π β§ π₯ β β) β (π β {π₯}) = (π β {π₯})) |
3 | 2 | fveq2d 6895 | . . 3 β’ ((π = π β§ π₯ β β) β (volβ(π β {π₯})) = (volβ(π β {π₯}))) |
4 | 3 | itgeq2dv 25532 | . 2 β’ (π = π β β«β(volβ(π β {π₯})) dπ₯ = β«β(volβ(π β {π₯})) dπ₯) |
5 | dfarea 26702 | . 2 β’ area = (π β dom area β¦ β«β(volβ(π β {π₯})) dπ₯) | |
6 | itgex 25521 | . 2 β’ β«β(volβ(π β {π₯})) dπ₯ β V | |
7 | 4, 5, 6 | fvmpt 6998 | 1 β’ (π β dom area β (areaβπ) = β«β(volβ(π β {π₯})) dπ₯) |
Colors of variables: wff setvar class |
Syntax hints: β wi 4 β§ wa 395 = wceq 1540 β wcel 2105 {csn 4628 dom cdm 5676 β cima 5679 βcfv 6543 βcr 11112 volcvol 25213 β«citg 25368 areacarea 26697 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1796 ax-4 1810 ax-5 1912 ax-6 1970 ax-7 2010 ax-8 2107 ax-9 2115 ax-10 2136 ax-11 2153 ax-12 2170 ax-ext 2702 ax-sep 5299 ax-nul 5306 ax-pow 5363 ax-pr 5427 ax-un 7728 ax-cnex 11169 ax-resscn 11170 ax-1cn 11171 ax-icn 11172 ax-addcl 11173 ax-addrcl 11174 ax-mulcl 11175 ax-mulrcl 11176 ax-mulcom 11177 ax-addass 11178 ax-mulass 11179 ax-distr 11180 ax-i2m1 11181 ax-1ne0 11182 ax-1rid 11183 ax-rnegex 11184 ax-rrecex 11185 ax-cnre 11186 ax-pre-lttri 11187 ax-pre-lttrn 11188 ax-pre-ltadd 11189 ax-pre-mulgt0 11190 |
This theorem depends on definitions: df-bi 206 df-an 396 df-or 845 df-3or 1087 df-3an 1088 df-tru 1543 df-fal 1553 df-ex 1781 df-nf 1785 df-sb 2067 df-mo 2533 df-eu 2562 df-clab 2709 df-cleq 2723 df-clel 2809 df-nfc 2884 df-ne 2940 df-nel 3046 df-ral 3061 df-rex 3070 df-reu 3376 df-rab 3432 df-v 3475 df-sbc 3778 df-csb 3894 df-dif 3951 df-un 3953 df-in 3955 df-ss 3965 df-pss 3967 df-nul 4323 df-if 4529 df-pw 4604 df-sn 4629 df-pr 4631 df-op 4635 df-uni 4909 df-iun 4999 df-br 5149 df-opab 5211 df-mpt 5232 df-tr 5266 df-id 5574 df-eprel 5580 df-po 5588 df-so 5589 df-fr 5631 df-we 5633 df-xp 5682 df-rel 5683 df-cnv 5684 df-co 5685 df-dm 5686 df-rn 5687 df-res 5688 df-ima 5689 df-pred 6300 df-ord 6367 df-on 6368 df-lim 6369 df-suc 6370 df-iota 6495 df-fun 6545 df-fn 6546 df-f 6547 df-f1 6548 df-fo 6549 df-f1o 6550 df-fv 6551 df-riota 7368 df-ov 7415 df-oprab 7416 df-mpo 7417 df-om 7859 df-1st 7978 df-2nd 7979 df-frecs 8269 df-wrecs 8300 df-recs 8374 df-rdg 8413 df-er 8706 df-en 8943 df-dom 8944 df-sdom 8945 df-pnf 11255 df-mnf 11256 df-xr 11257 df-ltxr 11258 df-le 11259 df-sub 11451 df-neg 11452 df-nn 12218 df-n0 12478 df-z 12564 df-uz 12828 df-fz 13490 df-seq 13972 df-sum 15638 df-itg 25373 df-area 26698 |
This theorem is referenced by: areacirc 36885 arearect 42267 areaquad 42268 |
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