Teaching of the elements of arithmetic: a lost treatise of Diophantus from Alexandria? (Q809055)

The works on which the fame of Diophantus rests are: (1) the \textit{Arithmetica} (originally in thirteen books); (2) a tract \textit{On polygonal numbers}. Only six books of the former and a fragment of the latter survive in Greek. The remaining seven were considered to be lost until the recent discovery of four in an Arabic translation. Allusions in the \textit{Arithmetica} imply the existence of (3) a collection of propositions under the title of \textit{Porisms}, and another work (4) \textit{Moriastica} is mentioned only once, in a scholium to Iamblichus' commentary on Nicomachus' \textit{Arithmetica}. The author of the paper under review suggests the existence of a lost, fifth treatise of Diophantus entitled \textit{Teaching of the elements of arithmetic}. His claims are based on a scholium of an anonymous Byzantine commentator.