Proof

(related to Proposition: Distance in Normed Vector Spaces)

The properties of a distance follow immediately from the definition of the norm:

  1. \(\|x-y\|=0\) if and only if \(x=y\).
  2. Symmetry: \(\|x-y\|=\|-1(y-x)\|=|-1|\cdot\|y-x\|=\|y-x\|\) for all \(x,y\in (V,\|~\|)\).
  3. Symmetry: \(\|x-y\|=\|-1(y-x)\|=|-1|\cdot\|y-x\|=\|y-x\|\) for all \(x,y\in (V,\|~\|)\).

Thank you to the contributors under CC BY-SA 4.0!

Github:
bookofproofs


References

Bibliography

  1. Forster Otto: "Analysis 2, Differentialrechnung im \(\mathbb R^n\), Gewöhnliche Differentialgleichungen", Vieweg Studium, 1984