IMO 2017 Shortlist A6

Find all fun tions f : R Ñ R su h that fpfpxqfpyqq fpx yq “ fpxyq for all x,y P R. (Albania)

IMO 2017 Shortlist A6

Category: Algebra

Problem

Find all fun tions f : R Ñ R su h that fpfpxqfpyqq fpx yq “ fpxyq for all x,y P R. (Albania)