Wojciech Chachólski, Algebra 5B1467, Fall 2005


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Plan

Homework
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Date
Material covered
10 Oct
Chapter 3 sections 2,3,4
3 Oct
Chapter 1, section 11; Chapter 3, section 117
Categories and functors were discused. For a fixed commutative ring R, the group ring construction G--> R[G] was shonw to be a functor from the category of groups to the category of R algebras. In the saim vain it was shown that for a fixed group G, the group ring construction R-->R[G]  is also a functor between
the category of commutative rings to the cateogry of rings.
   The basic definitions related modules were presented

26 Sept
Chapter 2, section 107
We talked about localization of a ring with respect to multiplicative systems.
19 Sept I plan to talk about commutative rings (section 2 of chapter 2), maximal and prime ideals, I will talk about theorem 2.1 and corollary 2.2. I will introduce a categorical definition of a product. I plan to talk about localization (section 4 of chapter 2). I would like also to talk about modules over rings.
12 Sept
Chapter 2 section 1, 2 and 3
We continued talking about group rings. We discussed ideals and operations on them.  It was shown that the ring of integers and polynomial ring over a field are P.I.D's (all ideals are singly generated).  Characteristic of a ring was defined.
5 Sept
Chapter 2, section 1,2 and 3.
In the class we talked about rings and algebras over a fixed commutative ring R:
an algebra is a ring homomorphism f between R and S such that for any r in R and any s in S, f(r)s=sf(r) (the elements in R commute with those in S).
Language of categories was introduced. Several examples were presented:
the ring of integers, the fields of rational, real and complex numbers, Z/n, the algebra of matrices over a commutative ring and the group algebra.