Monday, 4/17 notes Old business: Group properties: * order * generators * subgroups * Aut(G) * conjugacy classe * abelian * simple Smallest simple: A5 (Galois, 1830's) * discuss its conjugacy classes * discuss its "presentation" briefly New business: Overview of "big" results of group theory * factoring polynomials => A5 is first non-solvable, => general quintic cannot be factored define: "solvable" group : series of abelian normal "divisors" define: fields, full shebang: Galois theory * classifying groups (look up "simple group" in MathWorld) (a) factor into simple groups (b) all simple groups: (1) cyclic, prime order (2) An, n>=5 (3) Lie-type Chevally groups (finite field Lie-analog) (4) Lie type (5) Sporadic groups (c) exactly 26 sporadic groups (!), biggest is the "monster" group Other directions: * Lie groups: - manifold and group - exponential map e^A where A is an element of tangent space; - Lie algebra (commutator relations of A's) gives local structure * Representations of groups => matrices, theoretical physics,