Metamath Proof Explorer


Theorem ncvspds

Description: Value of the distance function in terms of the norm of a normed subcomplex vector space. Equation 1 of Kreyszig p. 59. (Contributed by NM, 28-Nov-2006) (Revised by AV, 13-Oct-2021)

Ref Expression
Hypotheses ncvspds.n N = norm G
ncvspds.x X = Base G
ncvspds.p + ˙ = + G
ncvspds.d D = dist G
ncvspds.s · ˙ = G
Assertion ncvspds G NrmVec ℂVec A X B X A D B = N A + ˙ -1 · ˙ B

Proof

Step Hyp Ref Expression
1 ncvspds.n N = norm G
2 ncvspds.x X = Base G
3 ncvspds.p + ˙ = + G
4 ncvspds.d D = dist G
5 ncvspds.s · ˙ = G
6 elin G NrmVec ℂVec G NrmVec G ℂVec
7 nvcnlm G NrmVec G NrmMod
8 nlmngp G NrmMod G NrmGrp
9 7 8 syl G NrmVec G NrmGrp
10 9 adantr G NrmVec G ℂVec G NrmGrp
11 6 10 sylbi G NrmVec ℂVec G NrmGrp
12 eqid - G = - G
13 1 2 12 4 ngpds G NrmGrp A X B X A D B = N A - G B
14 11 13 syl3an1 G NrmVec ℂVec A X B X A D B = N A - G B
15 id G ℂVec G ℂVec
16 15 cvsclm G ℂVec G CMod
17 6 16 simplbiim G NrmVec ℂVec G CMod
18 eqid Scalar G = Scalar G
19 2 3 12 18 5 clmvsubval G CMod A X B X A - G B = A + ˙ -1 · ˙ B
20 17 19 syl3an1 G NrmVec ℂVec A X B X A - G B = A + ˙ -1 · ˙ B
21 20 fveq2d G NrmVec ℂVec A X B X N A - G B = N A + ˙ -1 · ˙ B
22 14 21 eqtrd G NrmVec ℂVec A X B X A D B = N A + ˙ -1 · ˙ B