Metamath Proof Explorer


Theorem itg2leub

Description: Any upper bound on the integrals of all simple functions G dominated by F is greater than ( S.2F ) , the least upper bound. (Contributed by Mario Carneiro, 28-Jun-2014)

Ref Expression
Assertion itg2leub F:0+∞A*2FAgdom1gfF1gA

Proof

Step Hyp Ref Expression
1 eqid x|gdom1gfFx=1g=x|gdom1gfFx=1g
2 1 itg2val F:0+∞2F=supx|gdom1gfFx=1g*<
3 2 adantr F:0+∞A*2F=supx|gdom1gfFx=1g*<
4 3 breq1d F:0+∞A*2FAsupx|gdom1gfFx=1g*<A
5 1 itg2lcl x|gdom1gfFx=1g*
6 supxrleub x|gdom1gfFx=1g*A*supx|gdom1gfFx=1g*<Azx|gdom1gfFx=1gzA
7 5 6 mpan A*supx|gdom1gfFx=1g*<Azx|gdom1gfFx=1gzA
8 7 adantl F:0+∞A*supx|gdom1gfFx=1g*<Azx|gdom1gfFx=1gzA
9 eqeq1 x=zx=1gz=1g
10 9 anbi2d x=zgfFx=1ggfFz=1g
11 10 rexbidv x=zgdom1gfFx=1ggdom1gfFz=1g
12 11 ralab zx|gdom1gfFx=1gzAzgdom1gfFz=1gzA
13 r19.23v gdom1gfFz=1gzAgdom1gfFz=1gzA
14 ancomst gfFz=1gzAz=1ggfFzA
15 impexp z=1ggfFzAz=1ggfFzA
16 14 15 bitri gfFz=1gzAz=1ggfFzA
17 16 ralbii gdom1gfFz=1gzAgdom1z=1ggfFzA
18 13 17 bitr3i gdom1gfFz=1gzAgdom1z=1ggfFzA
19 18 albii zgdom1gfFz=1gzAzgdom1z=1ggfFzA
20 ralcom4 gdom1zz=1ggfFzAzgdom1z=1ggfFzA
21 fvex 1gV
22 breq1 z=1gzA1gA
23 22 imbi2d z=1ggfFzAgfF1gA
24 21 23 ceqsalv zz=1ggfFzAgfF1gA
25 24 ralbii gdom1zz=1ggfFzAgdom1gfF1gA
26 20 25 bitr3i zgdom1z=1ggfFzAgdom1gfF1gA
27 19 26 bitri zgdom1gfFz=1gzAgdom1gfF1gA
28 12 27 bitri zx|gdom1gfFx=1gzAgdom1gfF1gA
29 8 28 bitrdi F:0+∞A*supx|gdom1gfFx=1g*<Agdom1gfF1gA
30 4 29 bitrd F:0+∞A*2FAgdom1gfF1gA