The Department of Mathematics has a public chat room in the worldwide network of servers supporting the matrix protocol. In this room, participants can discuss anything relating to Mathematics or seek answers to math questions.

The choice of "matrix" was based on the fact that this service is not centralized, not controlled by a single entity such as a for profit company, and it also supports the mathematical notation through the TeX conventions.

The address of the room is
#umath.aegean.gr:matrix.org
You can connect to this room from any matrix server, for example through
https://app.element.io
Support for TeX must be enabled by the user. Instructions, on how to do this are here.