Fernando Galván, José Francisco2023-06-202023-06-2020020002-994710.1090/S0002-9947-02-02956-2https://hdl.handle.net/20.500.14352/57241Let A be an analytic ring. We show:(1) A has finite Pythagoras number if and only if its real dimension is 2, and (2) if every positive semidefinite element of A is a sum of squares, then A is real and has real dimension 2.engjournal articlehttp://www.ams.org/journals/tran/2002-354-05/S0002-9947-02-02956-http://www.ams.org/restricted access511512.7Analytic ringPositive semidefnite elementSum of squaresPythagoras number.Teoría de númerosGeometria algebraica1205 Teoría de Números1201.01 Geometría Algebraica