Zi Yang, Sham2008-05-122008-05-122008-05-122008-05-08http://hdl.handle.net/10012/3656The main goal of this Masters' thesis is to explore isomorphism types of quaternion algebras using the theory of quadratic forms, number theory and algebra. I would also present ways to characterize quaternion algebras, and talk about how quaternion algebras are important in Brauer groups by describing a theorem proved by Merkurjev in 1981.enquadratic formsquaternion algebrasMaster ThesisAccounting