New Thesis Statement and Introductions

     Chern is one of the leaders in differential geometry of the twentieth century. he use his math to define a lot theory that we don't know. he is a chinese but why he become a famous math- ematicians because of the string theory. Chern's work spreads over all the classic fields of differential geometry. It includes areas currently fashionable, perennial , the foundational, and some areas such as projective differential geometry and webs that have a lower profile. He published results in integral geometry, value distribution theory of holomorphic functions, and minimal submanifolds.

        chern use his math to show the scientist that we have this theory, but the problem is we still can not make it become true, we only can know string theory is to be a theory of quantum gravity, then the average size of a string should be somewhere near the length scale of quantum gravity, called the Planck length, which is about 10^-33 centimeters, or about a millionth of a billionth of a billionth of a billionth of a centimeter. 

       A important proof was the forerunner of other invariants which bear his name, Chern classes, Chern-Weil homomorphism and Chern-Simons invariants, which have become essential tools not only in differential geometry but in other areas of mathematics such as topology and algebraic geometry and also mathematical physics. A large part of modern algebraic geometry would not exist without Chern classes. 

His area of research was differential geometry where he studied the Chern characteristic classes in fibre spaces. These are important not only in mathematics but also in mathematical physics. He worked on characteristic classes during his 1943-45 visit to Princeton and, also at this time, he gave a now famous proof of theGauss-Bonnet formula.

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Introduction

      every scientist must is a mathematician. mathematician can measure space and maybe anything. chern is the famous Chinese American mathematician, he use his math to define the string theory(a very important theory), if  you can really understand it and use it. maybe we can pass the time go back 100 years ago, you can think about how special mathematician can do. also, he define and improve the differential geometry.