Homework on Jordan-Neumann Inner Product Space Characterization
Par Lucas le dimanche 23 septembre 2012, 19:41 - Mathématiques - Lien permanent
Here is an homework that revisits (in the simplest case of real vector space) the proof of 1935 by Jordan and von Neumann, that a vector normed space satisfying the parallelogram law can be equiped with an inner product: Borboleta_2012_Homework-on-Jordan-Neumann-Inner-Product-Spaces-Characterization.pdf.
In this proof, the triangular inequality proprety of the norm is invoked for a continuity argument, but otherwise not used.