--%>

Examples of groups

Examples of groups: We now start to survey a wide range of examples of groups (labelled by (A), (B), (C), . . . ). Most of these come from number theory. In all cases, the group axioms should be checked. This is easy for almost all of the examples, and will be left as an exercise except in the occasional more difficult or subtle case.

(A) Our first examples are groups of numbers under addition. To begin, each of the sets Z (the integers), Q (the rational numbers), R (the real numbers) and C (the complex numbers) forms a group under the binary operation + of addition (exercise). Clearly, the groups are all abelian.

(B) For any fixed n ≡ Z, the set nZ = {na : a ≡ Z} is a subgroup of Z (exercise). A few speci fic cases are:

0Z = {0};
1Z = ( -1)Z = Z;
2Z = ( -2)Z = {2a : a ≡ Z}
= the set of even integers:

   Related Questions in Mathematics

  • Q : Problem on Nash equilibrium In a

    In a project, employee and boss are working altogether. The employee can be sincere or insincere, and the Boss can either reward or penalize. The employee gets no benefit for being sincere but gets utility for being insincere (30), for getting rewarded (10) and for be

  • Q : State Measuring complexity Measuring

    Measuring complexity: Many algorithms have an integer n, or two integers m and n, as input - e.g., addition, multiplication, exponentiation, factorisation and primality testing. When we want to describe or analyse the `easiness' or `hardness' of the a

  • Q : Problem on augmented matrix Consider

    Consider the following system of linear equations.  (a) Write out t

  • Q : Numerical Analysis Hi, I was wondering

    Hi, I was wondering if there is anyone who can perform numerical analysis and write a code when required. Thanks

  • Q : Containee problem For queries Q 1 and Q

    For queries Q1 and Q2, we say Q1 is containedin Q2, denoted Q1 C Q2, iff Q1(D) C Q2

  • Q : Abstract Boolean Algebra I. Boolean

    I. Boolean Algebra Define an abstract Boolean Algebra, B,  as follows:  The three operations are:  +   ( x + y addition) ( x y multiplic

  • Q : Explain a rigorous theory for Brownian

    Explain a rigorous theory for Brownian motion developed by Wiener Norbert.

  • Q : Solve each equation by factoring A

    A college student invested part of a $25,000 inheritance at 7% interest and the rest at 6%.  If his annual interest is $1,670 how much did he invest at 6%?  If I told you the answer is $8,000, in your own words, using complete sentences, explain how you

  • Q : State Prime number theorem Prime number

    Prime number theorem: A big deal is known about the distribution of prime numbers and of the prime factors of a typical number. Most of the mathematics, although, is deep: while the results are often not too hard to state, the proofs are often diffic

  • Q : State Fermat algorithm The basic Fermat

    The basic Fermat algorithm is as follows: Assume that n is an odd positive integer. Set c = [√n] (`ceiling of √n '). Then we consider in turn the numbers c2 - n; (c+1)2 - n; (c+2)2 - n..... until a perfect square is found. If th