Typhoons in the Philippines storms impacting the Philippines in deadly seasons, see: Typhoons in the Philippines Approximately twenty tropical cyclones enter the Philippine Area of Responsibility yearly, an area which incorporates parts of the Pacific Ocean, South China Sea and the Philippine Archipelago (with the exception of Tawi-Tawi province). Among these cyclones, ten will be typhoons, with five having the potential to be destructive ones. The Philippines is "the most exposed country in the world to tropical storms" according to a Time Magazine article in 2013. In the Philippine languages, typhoons are called "bagyo". Typhoons can hit the Philippines any time of year, with
Lie group Lie groups are called "isomorphic" if there exists a bijective homomorphism between them whose inverse is also a Lie group homomorphism. Equivalently, it is a diffeomorphism which is also a group homomorphism. Isomorphic Lie groups necessarily have isomorphic Lie algebras; it is then reasonable to ask how isomorphism classes of Lie groups relate to isomorphism classes of Lie algebras. The first result in this direction is Lie's third theorem, which states that every finite-dimensional, real Lie algebra is the Lie algebra of some (linear) Lie group. One way to prove Lie's third theorem is to use Ado's theorem, which says