Duration: 21 weeks
Number of lectures per week: 3
End-of-year Examination: One 3-hour examination
This course continues the study of groups, rings and fields commenced in course 111. A large part of the course is devoted to Galois theory, in which techniques of modern algebra are applied to the problem of expressing the roots of a polynomial as functions of its coefficients. To any polynomial is associated a finite group, referred to as the Galois group of the polynomial. The roots of a polynomial can be expressed in terms of its coefficients by means of algebraic formulae involving only the operations of addition, subtraction, multiplication, division and the extraction of nth roots if and only if the Galois group of the polynomial is `solvable'. This result can be used to prove that there cannot exist any algebraic formula for the roots of a general quintic polynomial that involves only the algebraic operations of addition, subtraction, multiplication, division and the extraction of nth roots.
The course will also study certain topics in number theory, including the Chinese Remainder Theorem and the Law of Quadratic Reciprocity.
John B.Fraleigh, A first course in abstract algebra.
Ian Stewart, Galois theory.
H.M. Edwards, Galois theory.
May 6, 1999