Myrto Kallipoliti "A topological characterization of the plane and homogeneous continua" Characterizations of the plane is a classical topic in topology starting from the work of Moore in the beginning of the 20th century. In this talk we give a new topological characterization of the plane which distinguishes it among all the simply connected spaces. The proof is based on a characterization of the 2-sphere given by BIng. This theorem improves an earlier result of Papasoglu. Using the same methods we also show that simply connected homogeneous continua are not separated by arcs. This result is inspired by a result about finitely presented groups. (Joint work with P. Papasoglu)