Resumen de Cauchy functional equation problems concerning orthogonality

Jürg Rätz

• We confine ourselves to the conditional Cauchy functional equation of orthogonal additivity and deal with problems which arise in connection with the following subjects: Dimension 2 versus higher dimensions; Dependence on the range space; Modules as domain spaces; Gleason's Theorem; Disjoint additivity on normed Riesz spaces.