Massive gravity is the theory of graviton with mass. This idea has been researched for long time but all attempts had failed because of some ghost problems. In 2012, for the fist time, consistent theory of massive gravity was constructed as dGRT ghost-free massive gravity. And now it is expected to solve some cosmological problems. I introduce the theoretical aspects of massive gravity and its cosmological applications, as a review based on Refs  ～  .
首都大学東京, 2016-03-25, 修士（理学）