On Welschinger invariants of real del Pezzo surfaces

The real analogue of Gromov-Witten invariants was discovered
by Welschinger about ten years ago. One of the most interesting
applications of Welschinger invariants is enumeration of real rational
curves in real del Pezzo surfaces. We discuss several ways to compute
Welschinger invariants, stressing on the tropical side of the computation.
We demonstrate interesting phenomena in the behavior of Welschinger
invariants and discuss open problems.