Metamath Proof Explorer


Theorem cdj3lem3b

Description: Lemma for cdj3i . The second-component function T is bounded if the subspaces are completely disjoint. (Contributed by NM, 31-May-2005) (New usage is discouraged.)

Ref Expression
Hypotheses cdj3lem2.1 𝐴S
cdj3lem2.2 𝐵S
cdj3lem3.3 𝑇 = ( 𝑥 ∈ ( 𝐴 + 𝐵 ) ↦ ( 𝑤𝐵𝑧𝐴 𝑥 = ( 𝑧 + 𝑤 ) ) )
Assertion cdj3lem3b ( ∃ 𝑣 ∈ ℝ ( 0 < 𝑣 ∧ ∀ 𝑥𝐴𝑦𝐵 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) ) → ∃ 𝑣 ∈ ℝ ( 0 < 𝑣 ∧ ∀ 𝑢 ∈ ( 𝐴 + 𝐵 ) ( norm ‘ ( 𝑇𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ) )

Proof

Step Hyp Ref Expression
1 cdj3lem2.1 𝐴S
2 cdj3lem2.2 𝐵S
3 cdj3lem3.3 𝑇 = ( 𝑥 ∈ ( 𝐴 + 𝐵 ) ↦ ( 𝑤𝐵𝑧𝐴 𝑥 = ( 𝑧 + 𝑤 ) ) )
4 2 1 shscomi ( 𝐵 + 𝐴 ) = ( 𝐴 + 𝐵 )
5 2 sheli ( 𝑤𝐵𝑤 ∈ ℋ )
6 1 sheli ( 𝑧𝐴𝑧 ∈ ℋ )
7 ax-hvcom ( ( 𝑤 ∈ ℋ ∧ 𝑧 ∈ ℋ ) → ( 𝑤 + 𝑧 ) = ( 𝑧 + 𝑤 ) )
8 5 6 7 syl2an ( ( 𝑤𝐵𝑧𝐴 ) → ( 𝑤 + 𝑧 ) = ( 𝑧 + 𝑤 ) )
9 8 eqeq2d ( ( 𝑤𝐵𝑧𝐴 ) → ( 𝑥 = ( 𝑤 + 𝑧 ) ↔ 𝑥 = ( 𝑧 + 𝑤 ) ) )
10 9 rexbidva ( 𝑤𝐵 → ( ∃ 𝑧𝐴 𝑥 = ( 𝑤 + 𝑧 ) ↔ ∃ 𝑧𝐴 𝑥 = ( 𝑧 + 𝑤 ) ) )
11 10 riotabiia ( 𝑤𝐵𝑧𝐴 𝑥 = ( 𝑤 + 𝑧 ) ) = ( 𝑤𝐵𝑧𝐴 𝑥 = ( 𝑧 + 𝑤 ) )
12 4 11 mpteq12i ( 𝑥 ∈ ( 𝐵 + 𝐴 ) ↦ ( 𝑤𝐵𝑧𝐴 𝑥 = ( 𝑤 + 𝑧 ) ) ) = ( 𝑥 ∈ ( 𝐴 + 𝐵 ) ↦ ( 𝑤𝐵𝑧𝐴 𝑥 = ( 𝑧 + 𝑤 ) ) )
13 3 12 eqtr4i 𝑇 = ( 𝑥 ∈ ( 𝐵 + 𝐴 ) ↦ ( 𝑤𝐵𝑧𝐴 𝑥 = ( 𝑤 + 𝑧 ) ) )
14 2 1 13 cdj3lem2b ( ∃ 𝑣 ∈ ℝ ( 0 < 𝑣 ∧ ∀ 𝑥𝐵𝑦𝐴 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) ) → ∃ 𝑣 ∈ ℝ ( 0 < 𝑣 ∧ ∀ 𝑢 ∈ ( 𝐵 + 𝐴 ) ( norm ‘ ( 𝑇𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ) )
15 fveq2 ( 𝑥 = 𝑡 → ( norm𝑥 ) = ( norm𝑡 ) )
16 15 oveq1d ( 𝑥 = 𝑡 → ( ( norm𝑥 ) + ( norm𝑦 ) ) = ( ( norm𝑡 ) + ( norm𝑦 ) ) )
17 fvoveq1 ( 𝑥 = 𝑡 → ( norm ‘ ( 𝑥 + 𝑦 ) ) = ( norm ‘ ( 𝑡 + 𝑦 ) ) )
18 17 oveq2d ( 𝑥 = 𝑡 → ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) = ( 𝑣 · ( norm ‘ ( 𝑡 + 𝑦 ) ) ) )
19 16 18 breq12d ( 𝑥 = 𝑡 → ( ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) ↔ ( ( norm𝑡 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + 𝑦 ) ) ) ) )
20 fveq2 ( 𝑦 = → ( norm𝑦 ) = ( norm ) )
21 20 oveq2d ( 𝑦 = → ( ( norm𝑡 ) + ( norm𝑦 ) ) = ( ( norm𝑡 ) + ( norm ) ) )
22 oveq2 ( 𝑦 = → ( 𝑡 + 𝑦 ) = ( 𝑡 + ) )
23 22 fveq2d ( 𝑦 = → ( norm ‘ ( 𝑡 + 𝑦 ) ) = ( norm ‘ ( 𝑡 + ) ) )
24 23 oveq2d ( 𝑦 = → ( 𝑣 · ( norm ‘ ( 𝑡 + 𝑦 ) ) ) = ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) )
25 21 24 breq12d ( 𝑦 = → ( ( ( norm𝑡 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + 𝑦 ) ) ) ↔ ( ( norm𝑡 ) + ( norm ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ) )
26 19 25 cbvral2vw ( ∀ 𝑥𝐴𝑦𝐵 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) ↔ ∀ 𝑡𝐴𝐵 ( ( norm𝑡 ) + ( norm ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) )
27 ralcom ( ∀ 𝑡𝐴𝐵 ( ( norm𝑡 ) + ( norm ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ↔ ∀ 𝐵𝑡𝐴 ( ( norm𝑡 ) + ( norm ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) )
28 2 sheli ( 𝑥𝐵𝑥 ∈ ℋ )
29 normcl ( 𝑥 ∈ ℋ → ( norm𝑥 ) ∈ ℝ )
30 28 29 syl ( 𝑥𝐵 → ( norm𝑥 ) ∈ ℝ )
31 30 recnd ( 𝑥𝐵 → ( norm𝑥 ) ∈ ℂ )
32 1 sheli ( 𝑦𝐴𝑦 ∈ ℋ )
33 normcl ( 𝑦 ∈ ℋ → ( norm𝑦 ) ∈ ℝ )
34 32 33 syl ( 𝑦𝐴 → ( norm𝑦 ) ∈ ℝ )
35 34 recnd ( 𝑦𝐴 → ( norm𝑦 ) ∈ ℂ )
36 addcom ( ( ( norm𝑥 ) ∈ ℂ ∧ ( norm𝑦 ) ∈ ℂ ) → ( ( norm𝑥 ) + ( norm𝑦 ) ) = ( ( norm𝑦 ) + ( norm𝑥 ) ) )
37 31 35 36 syl2an ( ( 𝑥𝐵𝑦𝐴 ) → ( ( norm𝑥 ) + ( norm𝑦 ) ) = ( ( norm𝑦 ) + ( norm𝑥 ) ) )
38 ax-hvcom ( ( 𝑥 ∈ ℋ ∧ 𝑦 ∈ ℋ ) → ( 𝑥 + 𝑦 ) = ( 𝑦 + 𝑥 ) )
39 28 32 38 syl2an ( ( 𝑥𝐵𝑦𝐴 ) → ( 𝑥 + 𝑦 ) = ( 𝑦 + 𝑥 ) )
40 39 fveq2d ( ( 𝑥𝐵𝑦𝐴 ) → ( norm ‘ ( 𝑥 + 𝑦 ) ) = ( norm ‘ ( 𝑦 + 𝑥 ) ) )
41 40 oveq2d ( ( 𝑥𝐵𝑦𝐴 ) → ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) = ( 𝑣 · ( norm ‘ ( 𝑦 + 𝑥 ) ) ) )
42 37 41 breq12d ( ( 𝑥𝐵𝑦𝐴 ) → ( ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) ↔ ( ( norm𝑦 ) + ( norm𝑥 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑦 + 𝑥 ) ) ) ) )
43 42 ralbidva ( 𝑥𝐵 → ( ∀ 𝑦𝐴 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) ↔ ∀ 𝑦𝐴 ( ( norm𝑦 ) + ( norm𝑥 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑦 + 𝑥 ) ) ) ) )
44 43 ralbiia ( ∀ 𝑥𝐵𝑦𝐴 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) ↔ ∀ 𝑥𝐵𝑦𝐴 ( ( norm𝑦 ) + ( norm𝑥 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑦 + 𝑥 ) ) ) )
45 fveq2 ( 𝑥 = → ( norm𝑥 ) = ( norm ) )
46 45 oveq2d ( 𝑥 = → ( ( norm𝑦 ) + ( norm𝑥 ) ) = ( ( norm𝑦 ) + ( norm ) ) )
47 oveq2 ( 𝑥 = → ( 𝑦 + 𝑥 ) = ( 𝑦 + ) )
48 47 fveq2d ( 𝑥 = → ( norm ‘ ( 𝑦 + 𝑥 ) ) = ( norm ‘ ( 𝑦 + ) ) )
49 48 oveq2d ( 𝑥 = → ( 𝑣 · ( norm ‘ ( 𝑦 + 𝑥 ) ) ) = ( 𝑣 · ( norm ‘ ( 𝑦 + ) ) ) )
50 46 49 breq12d ( 𝑥 = → ( ( ( norm𝑦 ) + ( norm𝑥 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑦 + 𝑥 ) ) ) ↔ ( ( norm𝑦 ) + ( norm ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑦 + ) ) ) ) )
51 fveq2 ( 𝑦 = 𝑡 → ( norm𝑦 ) = ( norm𝑡 ) )
52 51 oveq1d ( 𝑦 = 𝑡 → ( ( norm𝑦 ) + ( norm ) ) = ( ( norm𝑡 ) + ( norm ) ) )
53 fvoveq1 ( 𝑦 = 𝑡 → ( norm ‘ ( 𝑦 + ) ) = ( norm ‘ ( 𝑡 + ) ) )
54 53 oveq2d ( 𝑦 = 𝑡 → ( 𝑣 · ( norm ‘ ( 𝑦 + ) ) ) = ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) )
55 52 54 breq12d ( 𝑦 = 𝑡 → ( ( ( norm𝑦 ) + ( norm ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑦 + ) ) ) ↔ ( ( norm𝑡 ) + ( norm ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ) )
56 50 55 cbvral2vw ( ∀ 𝑥𝐵𝑦𝐴 ( ( norm𝑦 ) + ( norm𝑥 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑦 + 𝑥 ) ) ) ↔ ∀ 𝐵𝑡𝐴 ( ( norm𝑡 ) + ( norm ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) )
57 44 56 bitr2i ( ∀ 𝐵𝑡𝐴 ( ( norm𝑡 ) + ( norm ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ↔ ∀ 𝑥𝐵𝑦𝐴 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) )
58 26 27 57 3bitri ( ∀ 𝑥𝐴𝑦𝐵 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) ↔ ∀ 𝑥𝐵𝑦𝐴 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) )
59 58 anbi2i ( ( 0 < 𝑣 ∧ ∀ 𝑥𝐴𝑦𝐵 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) ) ↔ ( 0 < 𝑣 ∧ ∀ 𝑥𝐵𝑦𝐴 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) ) )
60 59 rexbii ( ∃ 𝑣 ∈ ℝ ( 0 < 𝑣 ∧ ∀ 𝑥𝐴𝑦𝐵 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) ) ↔ ∃ 𝑣 ∈ ℝ ( 0 < 𝑣 ∧ ∀ 𝑥𝐵𝑦𝐴 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) ) )
61 1 2 shscomi ( 𝐴 + 𝐵 ) = ( 𝐵 + 𝐴 )
62 61 raleqi ( ∀ 𝑢 ∈ ( 𝐴 + 𝐵 ) ( norm ‘ ( 𝑇𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ↔ ∀ 𝑢 ∈ ( 𝐵 + 𝐴 ) ( norm ‘ ( 𝑇𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) )
63 62 anbi2i ( ( 0 < 𝑣 ∧ ∀ 𝑢 ∈ ( 𝐴 + 𝐵 ) ( norm ‘ ( 𝑇𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ) ↔ ( 0 < 𝑣 ∧ ∀ 𝑢 ∈ ( 𝐵 + 𝐴 ) ( norm ‘ ( 𝑇𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ) )
64 63 rexbii ( ∃ 𝑣 ∈ ℝ ( 0 < 𝑣 ∧ ∀ 𝑢 ∈ ( 𝐴 + 𝐵 ) ( norm ‘ ( 𝑇𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ) ↔ ∃ 𝑣 ∈ ℝ ( 0 < 𝑣 ∧ ∀ 𝑢 ∈ ( 𝐵 + 𝐴 ) ( norm ‘ ( 𝑇𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ) )
65 14 60 64 3imtr4i ( ∃ 𝑣 ∈ ℝ ( 0 < 𝑣 ∧ ∀ 𝑥𝐴𝑦𝐵 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) ) → ∃ 𝑣 ∈ ℝ ( 0 < 𝑣 ∧ ∀ 𝑢 ∈ ( 𝐴 + 𝐵 ) ( norm ‘ ( 𝑇𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ) )