Poczta Polska (The Polish Post) has issued a special postcard for the occasion of the 100th Anniversary of the Polish Mathematical Society. It will be available at the philatelic stand at the post office at ul. Westerplatte in Kraków. In April, it will be possible to get it stamped.
The stamped postcard will be available for purchase from April 5th for three weeks in the philatelic shop.
Regional Special Postcard from Szczecin
The Polish Post in Szczecin issued a special postcard for the occasion of the 100th Anniversary of the Polish Mathematical Society and the Jubilee Year of Mathematics. It is available for purchase at the Szczecin 1 and Stargard 1 post offices. Date of placement on the market: April 8th 2019, circulation: 200.