Metamath Proof Explorer


Theorem ovollb

Description: The outer volume is a lower bound on the sum of all interval coverings of A . (Contributed by Mario Carneiro, 15-Jun-2014)

Ref Expression
Hypothesis ovollb.1 S = seq 1 + abs F
Assertion ovollb F : 2 A ran . F vol * A sup ran S * <

Proof

Step Hyp Ref Expression
1 ovollb.1 S = seq 1 + abs F
2 simpr F : 2 A ran . F A ran . F
3 ioof . : * × * 𝒫
4 simpl F : 2 A ran . F F : 2
5 inss2 2 2
6 rexpssxrxp 2 * × *
7 5 6 sstri 2 * × *
8 fss F : 2 2 * × * F : * × *
9 4 7 8 sylancl F : 2 A ran . F F : * × *
10 fco . : * × * 𝒫 F : * × * . F : 𝒫
11 3 9 10 sylancr F : 2 A ran . F . F : 𝒫
12 11 frnd F : 2 A ran . F ran . F 𝒫
13 sspwuni ran . F 𝒫 ran . F
14 12 13 sylib F : 2 A ran . F ran . F
15 2 14 sstrd F : 2 A ran . F A
16 eqid y * | f 2 A ran . f y = sup ran seq 1 + abs f * < = y * | f 2 A ran . f y = sup ran seq 1 + abs f * <
17 16 ovolval A vol * A = sup y * | f 2 A ran . f y = sup ran seq 1 + abs f * < * <
18 15 17 syl F : 2 A ran . F vol * A = sup y * | f 2 A ran . f y = sup ran seq 1 + abs f * < * <
19 ssrab2 y * | f 2 A ran . f y = sup ran seq 1 + abs f * < *
20 16 1 elovolmr F : 2 A ran . F sup ran S * < y * | f 2 A ran . f y = sup ran seq 1 + abs f * <
21 infxrlb y * | f 2 A ran . f y = sup ran seq 1 + abs f * < * sup ran S * < y * | f 2 A ran . f y = sup ran seq 1 + abs f * < sup y * | f 2 A ran . f y = sup ran seq 1 + abs f * < * < sup ran S * <
22 19 20 21 sylancr F : 2 A ran . F sup y * | f 2 A ran . f y = sup ran seq 1 + abs f * < * < sup ran S * <
23 18 22 eqbrtrd F : 2 A ran . F vol * A sup ran S * <