Metamath Proof Explorer


Theorem volsuplem

Description: Lemma for volsup . (Contributed by Mario Carneiro, 4-Jul-2014)

Ref Expression
Assertion volsuplem n F n F n + 1 A B A F A F B

Proof

Step Hyp Ref Expression
1 fveq2 x = A F x = F A
2 1 sseq2d x = A F A F x F A F A
3 2 imbi2d x = A n F n F n + 1 A F A F x n F n F n + 1 A F A F A
4 fveq2 x = k F x = F k
5 4 sseq2d x = k F A F x F A F k
6 5 imbi2d x = k n F n F n + 1 A F A F x n F n F n + 1 A F A F k
7 fveq2 x = k + 1 F x = F k + 1
8 7 sseq2d x = k + 1 F A F x F A F k + 1
9 8 imbi2d x = k + 1 n F n F n + 1 A F A F x n F n F n + 1 A F A F k + 1
10 fveq2 x = B F x = F B
11 10 sseq2d x = B F A F x F A F B
12 11 imbi2d x = B n F n F n + 1 A F A F x n F n F n + 1 A F A F B
13 ssid F A F A
14 13 2a1i A n F n F n + 1 A F A F A
15 eluznn A k A k
16 fveq2 n = k F n = F k
17 fvoveq1 n = k F n + 1 = F k + 1
18 16 17 sseq12d n = k F n F n + 1 F k F k + 1
19 18 rspccva n F n F n + 1 k F k F k + 1
20 15 19 sylan2 n F n F n + 1 A k A F k F k + 1
21 20 anassrs n F n F n + 1 A k A F k F k + 1
22 sstr2 F A F k F k F k + 1 F A F k + 1
23 21 22 syl5com n F n F n + 1 A k A F A F k F A F k + 1
24 23 expcom k A n F n F n + 1 A F A F k F A F k + 1
25 24 a2d k A n F n F n + 1 A F A F k n F n F n + 1 A F A F k + 1
26 3 6 9 12 14 25 uzind4 B A n F n F n + 1 A F A F B
27 26 com12 n F n F n + 1 A B A F A F B
28 27 impr n F n F n + 1 A B A F A F B