-
Recent Posts
Archives
- March 2023
- January 2023
- May 2020
- April 2020
- March 2020
- June 2018
- July 2016
- June 2016
- May 2016
- March 2015
- February 2015
- January 2015
- December 2014
- December 2013
- November 2013
- July 2013
- June 2013
- May 2013
- March 2013
- February 2013
- January 2013
- December 2012
- November 2012
- October 2012
- September 2012
- August 2012
- April 2012
- March 2012
- February 2012
- January 2012
- December 2011
- November 2011
- October 2011
Categories
Meta
Pages
Monthly Archives: October 2012
Introduction to Ring Theory (8)
Matrix Rings In this post, we’ll be entering the matrix. Let R be a ring. The ring Mn×n(R) is the set of matrices whose entries are elements of R, where the addition and multiplication operations are given by the usual matrix addition … Continue reading
Posted in Notes
Tagged advanced, cramer's rule, determinants, matrix rings, ring theory, rings, simple rings
Leave a comment
Introduction to Ring Theory (7)
Polynomial Rings A polynomial over a ring R is an expression of the form: , where , and . Let’s get some standard terminology out of the way. The element ai is called the coefficient of xi. The largest n for which an ≠ 0 is called … Continue reading
Posted in Notes
Tagged cryptography, derivatives, factor theorem, polynomials, remainder theorem, ring theory, secret sharing
Leave a comment
Introduction to Ring Theory (6)
Let’s keep stock of what we’ve covered so far for ring theory, and compare it to the case of groups. There are loads of parallels between the two cases. G is a group R is a ring. Abelian groups. Commutative … Continue reading
Introduction to Ring Theory (5)
Our first order of the day is to state the correspondence between the ideals and subrings of R/I and those of R. This is totally analogous to the case of groups. Theorem. Let I be an ideal of R. There are 1-1 … Continue reading
Posted in Notes
Tagged advanced, chinese remainder theorem, ideals, maximal ideals, prime ideals, ring theory, rings
Leave a comment
Introduction to Ring Theory (4)
It’s now time to talk about homomorphisms. Definition. Let R, S be rings. A function f : R → S is a ring homomorphism if it satisfies the following: f(1R) = 1S; f(x+y) = f(x) + f(y) for all x, y in … Continue reading
Introduction to Ring Theory (3)
Ideals and Ring Quotients Suppose I is a subgroup of (R, +). Since + is abelian, I is automatically a normal subgroup and we get the group quotient (R/I, +). One asks when we can define the product operation on R/I. To be specific, each … Continue reading
Posted in Notes
Tagged advanced, gaussian integers, generated ideals, ideals, principal ideals, ring quotients, ring theory
Leave a comment
Introduction to Ring Theory (2)
Subrings Just like groups have subgroups, we have: Definition. A subset S of a ring R is a subring if it satisfies the following: ; ; . The first two conditions imply that S is a subgroup of (R, +). Together with … Continue reading
Introduction to Ring Theory (1)
Recall that in groups, one has only a binary operation *. Rings are algebraic structures with addition and multiplication operations – and consistency is ensured by the distributive property. Definition. A ring R is a set together with two binary operations: … Continue reading
Posted in Notes
Tagged advanced, characteristic, commutative rings, distributive property, division rings, fields, integral domains, quaternions, ring theory, rings, units, zero-divisors
Leave a comment
Random Walk and Differential Equations (II)
1-Dimensional Heat Equation Consider the case of 1-dimensional random walk. The equation (*) from the previous post gives: for t≥0. Suppose the intervals between successive time/space points are variable. Let’s rewrite it in the following form: Setting δt ≈ ε2 and δx ≈ ε, we divide both … Continue reading
Mathematics and Such 