IMO Shortlist 2015 problem A2
Dodao/la:
arhiva30. kolovoza 2018. Determine all functions $f:\mathbb{Z}\rightarrow\mathbb{Z}$ with the property that \[f(x-f(y))=f(f(x))-f(y)-1\]holds for all $x,y\in\mathbb{Z}$.
\begin{flushright}\emph{(Croatia)}\end{flushright}
Izvor: https://www.imo-official.org/problems/IMO2015SL.pdf