TY - JOUR AB - This is a collection of problems composed by some participants of the workshop “Differential Geometry, Billiards, and Geometric Optics” that took place at CIRM on October 4–8, 2021. AU - Bialy, Misha AU - Fiorebe, Corentin AU - Glutsyuk, Alexey AU - Levi, Mark AU - Plakhov, Alexander AU - Tabachnikov, Serge ID - 10706 JF - Arnold Mathematical Journal SN - 2199-6792 TI - Open problems on billiards and geometric optics VL - 8 ER -