‎"RIESZ, FRIGYES & ERNST FISCHER. - THE ""FISCHER-RIESZ THEOREM""‎
‎Sur les systémes orthogonaux de fonctions. (Reisz) + Sur la convergence en moyenne. (Fischer). + Applications d'un théoreme sur la convergence en moyenne. (Fischer).‎

‎(Paris, Gauthier-Villars), 1907. 4to. No wrappers. In: ""Comptes Rendus Hebdomadaires des Séances de L'Academie des Sciences"", Tome 144, No 11, No. 19 and No. 21. Pp. (593-) 664 + pp. (1009-) 1080. + pp. (1137-) 1192.(3 entire issues offered).Reesz' paper: pp. 615-619. Fischer's paper: pp. 1022-1024 a. 1148-51. Nos 19 a. 21 with some small tears to outher margins. paper fragile. Sewing loose.‎

Reference : 48911

‎First apperance of two fundamental papers - Riesz setting forth the theorem and Fischer proving it - the mathematics of which later made it clear that there is an equivalence between matrix mechanics (Heisenberg) and wave mechanics (Schrödinger) in quantum physics.The Riesz-Fischer theorem of 1907, concerning the equivalence of the Hilbert space of sequences of convergent sums of squares with the space of functions of summable squares, formed the mathematical basis for demonstrating the equivalence of matrix mechanics and wave mechanics.‎