Metamath Proof Explorer


Theorem cdj3lem2b

Description: Lemma for cdj3i . The first-component function S is bounded if the subspaces are completely disjoint. (Contributed by NM, 26-May-2005) (New usage is discouraged.)

Ref Expression
Hypotheses cdj3lem2.1 𝐴S
cdj3lem2.2 𝐵S
cdj3lem2.3 𝑆 = ( 𝑥 ∈ ( 𝐴 + 𝐵 ) ↦ ( 𝑧𝐴𝑤𝐵 𝑥 = ( 𝑧 + 𝑤 ) ) )
Assertion cdj3lem2b ( ∃ 𝑣 ∈ ℝ ( 0 < 𝑣 ∧ ∀ 𝑥𝐴𝑦𝐵 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) ) → ∃ 𝑣 ∈ ℝ ( 0 < 𝑣 ∧ ∀ 𝑢 ∈ ( 𝐴 + 𝐵 ) ( norm ‘ ( 𝑆𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ) )

Proof

Step Hyp Ref Expression
1 cdj3lem2.1 𝐴S
2 cdj3lem2.2 𝐵S
3 cdj3lem2.3 𝑆 = ( 𝑥 ∈ ( 𝐴 + 𝐵 ) ↦ ( 𝑧𝐴𝑤𝐵 𝑥 = ( 𝑧 + 𝑤 ) ) )
4 1 2 cdj3lem1 ( ∃ 𝑣 ∈ ℝ ( 0 < 𝑣 ∧ ∀ 𝑥𝐴𝑦𝐵 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) ) → ( 𝐴𝐵 ) = 0 )
5 1 2 shseli ( 𝑢 ∈ ( 𝐴 + 𝐵 ) ↔ ∃ 𝑡𝐴𝐵 𝑢 = ( 𝑡 + ) )
6 5 biimpi ( 𝑢 ∈ ( 𝐴 + 𝐵 ) → ∃ 𝑡𝐴𝐵 𝑢 = ( 𝑡 + ) )
7 fveq2 ( 𝑥 = 𝑡 → ( norm𝑥 ) = ( norm𝑡 ) )
8 7 oveq1d ( 𝑥 = 𝑡 → ( ( norm𝑥 ) + ( norm𝑦 ) ) = ( ( norm𝑡 ) + ( norm𝑦 ) ) )
9 fvoveq1 ( 𝑥 = 𝑡 → ( norm ‘ ( 𝑥 + 𝑦 ) ) = ( norm ‘ ( 𝑡 + 𝑦 ) ) )
10 9 oveq2d ( 𝑥 = 𝑡 → ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) = ( 𝑣 · ( norm ‘ ( 𝑡 + 𝑦 ) ) ) )
11 8 10 breq12d ( 𝑥 = 𝑡 → ( ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) ↔ ( ( norm𝑡 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + 𝑦 ) ) ) ) )
12 fveq2 ( 𝑦 = → ( norm𝑦 ) = ( norm ) )
13 12 oveq2d ( 𝑦 = → ( ( norm𝑡 ) + ( norm𝑦 ) ) = ( ( norm𝑡 ) + ( norm ) ) )
14 oveq2 ( 𝑦 = → ( 𝑡 + 𝑦 ) = ( 𝑡 + ) )
15 14 fveq2d ( 𝑦 = → ( norm ‘ ( 𝑡 + 𝑦 ) ) = ( norm ‘ ( 𝑡 + ) ) )
16 15 oveq2d ( 𝑦 = → ( 𝑣 · ( norm ‘ ( 𝑡 + 𝑦 ) ) ) = ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) )
17 13 16 breq12d ( 𝑦 = → ( ( ( norm𝑡 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + 𝑦 ) ) ) ↔ ( ( norm𝑡 ) + ( norm ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ) )
18 11 17 rspc2v ( ( 𝑡𝐴𝐵 ) → ( ∀ 𝑥𝐴𝑦𝐵 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) → ( ( norm𝑡 ) + ( norm ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ) )
19 1 2 3 cdj3lem2 ( ( 𝑡𝐴𝐵 ∧ ( 𝐴𝐵 ) = 0 ) → ( 𝑆 ‘ ( 𝑡 + ) ) = 𝑡 )
20 19 3expa ( ( ( 𝑡𝐴𝐵 ) ∧ ( 𝐴𝐵 ) = 0 ) → ( 𝑆 ‘ ( 𝑡 + ) ) = 𝑡 )
21 20 fveq2d ( ( ( 𝑡𝐴𝐵 ) ∧ ( 𝐴𝐵 ) = 0 ) → ( norm ‘ ( 𝑆 ‘ ( 𝑡 + ) ) ) = ( norm𝑡 ) )
22 21 ad2ant2r ( ( ( ( 𝑡𝐴𝐵 ) ∧ ( ( norm𝑡 ) + ( norm ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ) ∧ ( ( 𝐴𝐵 ) = 0𝑣 ∈ ℝ ) ) → ( norm ‘ ( 𝑆 ‘ ( 𝑡 + ) ) ) = ( norm𝑡 ) )
23 2 sheli ( 𝐵 ∈ ℋ )
24 normge0 ( ∈ ℋ → 0 ≤ ( norm ) )
25 23 24 syl ( 𝐵 → 0 ≤ ( norm ) )
26 25 adantl ( ( 𝑡𝐴𝐵 ) → 0 ≤ ( norm ) )
27 1 sheli ( 𝑡𝐴𝑡 ∈ ℋ )
28 normcl ( 𝑡 ∈ ℋ → ( norm𝑡 ) ∈ ℝ )
29 27 28 syl ( 𝑡𝐴 → ( norm𝑡 ) ∈ ℝ )
30 normcl ( ∈ ℋ → ( norm ) ∈ ℝ )
31 23 30 syl ( 𝐵 → ( norm ) ∈ ℝ )
32 addge01 ( ( ( norm𝑡 ) ∈ ℝ ∧ ( norm ) ∈ ℝ ) → ( 0 ≤ ( norm ) ↔ ( norm𝑡 ) ≤ ( ( norm𝑡 ) + ( norm ) ) ) )
33 29 31 32 syl2an ( ( 𝑡𝐴𝐵 ) → ( 0 ≤ ( norm ) ↔ ( norm𝑡 ) ≤ ( ( norm𝑡 ) + ( norm ) ) ) )
34 26 33 mpbid ( ( 𝑡𝐴𝐵 ) → ( norm𝑡 ) ≤ ( ( norm𝑡 ) + ( norm ) ) )
35 34 adantr ( ( ( 𝑡𝐴𝐵 ) ∧ 𝑣 ∈ ℝ ) → ( norm𝑡 ) ≤ ( ( norm𝑡 ) + ( norm ) ) )
36 29 ad2antrr ( ( ( 𝑡𝐴𝐵 ) ∧ 𝑣 ∈ ℝ ) → ( norm𝑡 ) ∈ ℝ )
37 readdcl ( ( ( norm𝑡 ) ∈ ℝ ∧ ( norm ) ∈ ℝ ) → ( ( norm𝑡 ) + ( norm ) ) ∈ ℝ )
38 29 31 37 syl2an ( ( 𝑡𝐴𝐵 ) → ( ( norm𝑡 ) + ( norm ) ) ∈ ℝ )
39 38 adantr ( ( ( 𝑡𝐴𝐵 ) ∧ 𝑣 ∈ ℝ ) → ( ( norm𝑡 ) + ( norm ) ) ∈ ℝ )
40 hvaddcl ( ( 𝑡 ∈ ℋ ∧ ∈ ℋ ) → ( 𝑡 + ) ∈ ℋ )
41 27 23 40 syl2an ( ( 𝑡𝐴𝐵 ) → ( 𝑡 + ) ∈ ℋ )
42 normcl ( ( 𝑡 + ) ∈ ℋ → ( norm ‘ ( 𝑡 + ) ) ∈ ℝ )
43 41 42 syl ( ( 𝑡𝐴𝐵 ) → ( norm ‘ ( 𝑡 + ) ) ∈ ℝ )
44 remulcl ( ( 𝑣 ∈ ℝ ∧ ( norm ‘ ( 𝑡 + ) ) ∈ ℝ ) → ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ∈ ℝ )
45 43 44 sylan2 ( ( 𝑣 ∈ ℝ ∧ ( 𝑡𝐴𝐵 ) ) → ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ∈ ℝ )
46 45 ancoms ( ( ( 𝑡𝐴𝐵 ) ∧ 𝑣 ∈ ℝ ) → ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ∈ ℝ )
47 letr ( ( ( norm𝑡 ) ∈ ℝ ∧ ( ( norm𝑡 ) + ( norm ) ) ∈ ℝ ∧ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ∈ ℝ ) → ( ( ( norm𝑡 ) ≤ ( ( norm𝑡 ) + ( norm ) ) ∧ ( ( norm𝑡 ) + ( norm ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ) → ( norm𝑡 ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ) )
48 36 39 46 47 syl3anc ( ( ( 𝑡𝐴𝐵 ) ∧ 𝑣 ∈ ℝ ) → ( ( ( norm𝑡 ) ≤ ( ( norm𝑡 ) + ( norm ) ) ∧ ( ( norm𝑡 ) + ( norm ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ) → ( norm𝑡 ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ) )
49 35 48 mpand ( ( ( 𝑡𝐴𝐵 ) ∧ 𝑣 ∈ ℝ ) → ( ( ( norm𝑡 ) + ( norm ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) → ( norm𝑡 ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ) )
50 49 imp ( ( ( ( 𝑡𝐴𝐵 ) ∧ 𝑣 ∈ ℝ ) ∧ ( ( norm𝑡 ) + ( norm ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ) → ( norm𝑡 ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) )
51 50 an32s ( ( ( ( 𝑡𝐴𝐵 ) ∧ ( ( norm𝑡 ) + ( norm ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ) ∧ 𝑣 ∈ ℝ ) → ( norm𝑡 ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) )
52 51 adantrl ( ( ( ( 𝑡𝐴𝐵 ) ∧ ( ( norm𝑡 ) + ( norm ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ) ∧ ( ( 𝐴𝐵 ) = 0𝑣 ∈ ℝ ) ) → ( norm𝑡 ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) )
53 22 52 eqbrtrd ( ( ( ( 𝑡𝐴𝐵 ) ∧ ( ( norm𝑡 ) + ( norm ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ) ∧ ( ( 𝐴𝐵 ) = 0𝑣 ∈ ℝ ) ) → ( norm ‘ ( 𝑆 ‘ ( 𝑡 + ) ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) )
54 2fveq3 ( 𝑢 = ( 𝑡 + ) → ( norm ‘ ( 𝑆𝑢 ) ) = ( norm ‘ ( 𝑆 ‘ ( 𝑡 + ) ) ) )
55 fveq2 ( 𝑢 = ( 𝑡 + ) → ( norm𝑢 ) = ( norm ‘ ( 𝑡 + ) ) )
56 55 oveq2d ( 𝑢 = ( 𝑡 + ) → ( 𝑣 · ( norm𝑢 ) ) = ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) )
57 54 56 breq12d ( 𝑢 = ( 𝑡 + ) → ( ( norm ‘ ( 𝑆𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ↔ ( norm ‘ ( 𝑆 ‘ ( 𝑡 + ) ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ) )
58 53 57 syl5ibrcom ( ( ( ( 𝑡𝐴𝐵 ) ∧ ( ( norm𝑡 ) + ( norm ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) ) ∧ ( ( 𝐴𝐵 ) = 0𝑣 ∈ ℝ ) ) → ( 𝑢 = ( 𝑡 + ) → ( norm ‘ ( 𝑆𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ) )
59 58 exp31 ( ( 𝑡𝐴𝐵 ) → ( ( ( norm𝑡 ) + ( norm ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑡 + ) ) ) → ( ( ( 𝐴𝐵 ) = 0𝑣 ∈ ℝ ) → ( 𝑢 = ( 𝑡 + ) → ( norm ‘ ( 𝑆𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ) ) ) )
60 18 59 syld ( ( 𝑡𝐴𝐵 ) → ( ∀ 𝑥𝐴𝑦𝐵 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) → ( ( ( 𝐴𝐵 ) = 0𝑣 ∈ ℝ ) → ( 𝑢 = ( 𝑡 + ) → ( norm ‘ ( 𝑆𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ) ) ) )
61 60 com14 ( 𝑢 = ( 𝑡 + ) → ( ∀ 𝑥𝐴𝑦𝐵 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) → ( ( ( 𝐴𝐵 ) = 0𝑣 ∈ ℝ ) → ( ( 𝑡𝐴𝐵 ) → ( norm ‘ ( 𝑆𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ) ) ) )
62 61 com4t ( ( ( 𝐴𝐵 ) = 0𝑣 ∈ ℝ ) → ( ( 𝑡𝐴𝐵 ) → ( 𝑢 = ( 𝑡 + ) → ( ∀ 𝑥𝐴𝑦𝐵 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) → ( norm ‘ ( 𝑆𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ) ) ) )
63 62 rexlimdvv ( ( ( 𝐴𝐵 ) = 0𝑣 ∈ ℝ ) → ( ∃ 𝑡𝐴𝐵 𝑢 = ( 𝑡 + ) → ( ∀ 𝑥𝐴𝑦𝐵 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) → ( norm ‘ ( 𝑆𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ) ) )
64 6 63 syl5com ( 𝑢 ∈ ( 𝐴 + 𝐵 ) → ( ( ( 𝐴𝐵 ) = 0𝑣 ∈ ℝ ) → ( ∀ 𝑥𝐴𝑦𝐵 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) → ( norm ‘ ( 𝑆𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ) ) )
65 64 com3l ( ( ( 𝐴𝐵 ) = 0𝑣 ∈ ℝ ) → ( ∀ 𝑥𝐴𝑦𝐵 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) → ( 𝑢 ∈ ( 𝐴 + 𝐵 ) → ( norm ‘ ( 𝑆𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ) ) )
66 65 ralrimdv ( ( ( 𝐴𝐵 ) = 0𝑣 ∈ ℝ ) → ( ∀ 𝑥𝐴𝑦𝐵 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) → ∀ 𝑢 ∈ ( 𝐴 + 𝐵 ) ( norm ‘ ( 𝑆𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ) )
67 66 anim2d ( ( ( 𝐴𝐵 ) = 0𝑣 ∈ ℝ ) → ( ( 0 < 𝑣 ∧ ∀ 𝑥𝐴𝑦𝐵 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) ) → ( 0 < 𝑣 ∧ ∀ 𝑢 ∈ ( 𝐴 + 𝐵 ) ( norm ‘ ( 𝑆𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ) ) )
68 67 reximdva ( ( 𝐴𝐵 ) = 0 → ( ∃ 𝑣 ∈ ℝ ( 0 < 𝑣 ∧ ∀ 𝑥𝐴𝑦𝐵 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) ) → ∃ 𝑣 ∈ ℝ ( 0 < 𝑣 ∧ ∀ 𝑢 ∈ ( 𝐴 + 𝐵 ) ( norm ‘ ( 𝑆𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ) ) )
69 4 68 mpcom ( ∃ 𝑣 ∈ ℝ ( 0 < 𝑣 ∧ ∀ 𝑥𝐴𝑦𝐵 ( ( norm𝑥 ) + ( norm𝑦 ) ) ≤ ( 𝑣 · ( norm ‘ ( 𝑥 + 𝑦 ) ) ) ) → ∃ 𝑣 ∈ ℝ ( 0 < 𝑣 ∧ ∀ 𝑢 ∈ ( 𝐴 + 𝐵 ) ( norm ‘ ( 𝑆𝑢 ) ) ≤ ( 𝑣 · ( norm𝑢 ) ) ) )