Acquistapace, FrancescaBroglia, FabrizioFernando Galván, José FranciscoRuiz Sancho, Jesús María2023-06-202023-06-2020050012-959310.1016/j.ansens.2005.04.001https://hdl.handle.net/20.500.14352/49905We show that (i) every positive semidefinite meromorphic function germ on a surface is a sum of 4 squares of meromorphic function germs, and that (ii) every positive semidefinite global meromorphic function on a normal surface is a sum of 5 squares of global meromorphic functions.engjournal articlehttp://www.sciencedirect.com/science/article/pii/S0012959305000443http://www.sciencedirect.com/restricted access512.7Pythagoras numberAnalytic functionAnalytic function germMeromorphic functionMeromorphic function germGeometria algebraica1201.01 Geometría Algebraica