IMO 2020 Shortlist A6
Determine all functions f : Z Ñ Z such that fa2b2 pa bq “ afpaq bfpbq for every a,b P Z. Here, fn denotes the nth iterat...
Category: Algebra
Problem
Determine all functions f : Z Ñ Z such that
fa2b2 pa bq “ afpaq bfpbq for every a,b P Z. Here, fn denotes the nth iteration of f, i.e., f0 pxq “ x and fn1
pxq “ fpfn
pxqq for all n ě 0.
(Slovakia) Shortlisted problems 5