23.10.2014 Views

ABSTRACT ALGEBRA - University of Sulaimani

ABSTRACT ALGEBRA - University of Sulaimani

ABSTRACT ALGEBRA - University of Sulaimani

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

<strong>University</strong> <strong>of</strong> <strong>Sulaimani</strong><br />

College <strong>of</strong> Science<br />

Department <strong>of</strong> Mathematics<br />

<strong>ABSTRACT</strong> <strong>ALGEBRA</strong><br />

Course Coordinator<br />

Dr. Kawa Ahmed Hasan<br />

2010-2011


@<br />

‘ŠŽíØ@ðØímŠóq<br />

óØóŠŽíØ@ðäbØbníàbà@ïÜ@ì@‘‹qŠói@ñbnŽíàbà@<br />

Course Coordinator and the list <strong>of</strong> teachers on<br />

this course@<br />

@@<br />

@@Abstract Algebra @@@@@@@@Z‘ŠŽíØ@õìbä<br />

@@<br />

@@Z‘‹qŠói@ñbnŽíàbà<br />

@@Assistant Pr<strong>of</strong>essor Dr. Adil Kadir Jabbar<br />

@@<br />

@@Z@wïÜŽíØ@O@•ói@ðäb“ïä@ìbä<br />

@@Department <strong>of</strong> Mathematics-College <strong>of</strong> Science<br />

@@<br />

@@Z@‘‹q@Šói@ñbníàbà@ói@熋Ø@ñ‡äòíîóq<br />

@@HDr. Kawa Ahmed HasanI<br />

E-mail@Z@ðäŽìÙÝï÷@ñ‡îŠói<br />

@@adilkj@gmail.com<br />

kawa79b@gmail.com<br />

@@<br />

@@<br />

@@@


óØóŠŽíØ@ñóbåŽïq@ì@ðØó“Žïq<br />

Course Overview<br />

Abstract Algebra is one <strong>of</strong> the important subjects in mathematics it<br />

consists <strong>of</strong> three parts Group Theory, Ring Theory and Field Theory.<br />

The present course deals only with the Group Theory and Ring Theory.<br />

@@Part I : Group Theory<br />

The concept <strong>of</strong> the group has been introduced for the first time in<br />

1770 and extends to the twentieth century, but the major developments<br />

occurred in nineteenth century. This part will outline the origins <strong>of</strong> the<br />

main concepts, results, and theories discussed in a first course on group<br />

theory, for example, the concepts <strong>of</strong> abstract groups, normal subgroups,<br />

quotient groups, simple groups, free groups, isomorphisms,<br />

homomorphisms, automorphisms, composition series, direct products,<br />

the theorems <strong>of</strong> Lagrange, Cauchy, Cayley, Jordan-Holder, the theories<br />

<strong>of</strong> permutation groups and <strong>of</strong> abelian (commutative) groups. There are<br />

four major sources in the evolution <strong>of</strong> group theory, they are:<br />

1. Classical Algebra (Lagrange, 1770):<br />

Lagrange wrote his fundamental memoir " Reflections on the<br />

solution <strong>of</strong> algebraic equations" concerned polynomial<br />

equations. There were<br />

(i) Theoretical questions: dealing with the existence and nature <strong>of</strong><br />

the roots, for example, does every equation have a root ? how<br />

many roots are there ? are they real, complex, positive, negative ?<br />

(ii) Practical questions: dealing with methods for finding the roots.<br />

In the later, there were exact methods and approximate methods.<br />

2. Number Theory (Gauss, 1801):<br />

Gauss summarized and unified much <strong>of</strong> the number theory that<br />

preceded him. The work also suggested new directions which kipped<br />

mathematician occupied for the entire century. The groups appeared<br />

in four different guises : the additive group <strong>of</strong> integers modulo n ,<br />

that denoted by Z n , the multiplicative group <strong>of</strong> integers relatively<br />

prime to n , modulo n , the group <strong>of</strong> equivalence classes <strong>of</strong> binary<br />

quadratic forms, and the group <strong>of</strong> n − th roots <strong>of</strong> unity.<br />

3. Geometry (Klein, 1874):<br />

Klein has classified geometry as the study <strong>of</strong> invariants under<br />

various groups <strong>of</strong> transformations. Here there appear groups such


as the projective group, the group <strong>of</strong> rigid motions, the group <strong>of</strong><br />

similarities, the hyperbolic group, the elliptic group as well as the<br />

geometries associated with them.<br />

4. Analysis (Lie, 1874 ; Poincare and Klein, 1876):<br />

In 1874, Lie introduced his general theory <strong>of</strong> continuous<br />

transformation groups- essentially what we call Lie groups today,<br />

while Poincare and Klein began their work on " Automorphic<br />

functions " and the groups associated with them around 1876.<br />

Automorphic functions (which are generalizations <strong>of</strong> he circular,<br />

hyperbolic, elliptic, and other functions <strong>of</strong> elementary analysis)<br />

are functions <strong>of</strong> a complex variable z and there is a very famous<br />

group which is referred to Klein as a Klein 4- group.<br />

@@Part II : Ring Theory<br />

Among the most important examples <strong>of</strong> rings are the integers,<br />

polynomials, and matrices. Simple extensions <strong>of</strong> these examples are at<br />

the roots <strong>of</strong> ring theory and thus we have the following three examples:<br />

1. The integers Z can be thought <strong>of</strong> as the appropriate subdomain <strong>of</strong><br />

the field Q <strong>of</strong> rational numbers in which to do number theory.<br />

2. The polynomial rings R [x]<br />

and R [ x,<br />

y]<br />

in one and two variables,<br />

where R denotes the real numbers. In particular, while the roots <strong>of</strong> a<br />

polynomial in one variable constitute <strong>of</strong> discrete set <strong>of</strong> real numbers,<br />

the roots <strong>of</strong> a polynomial in two variables constitute <strong>of</strong> a curve in the<br />

plane a so-called algebraic curve.<br />

3. Square n × n matrices over the real numbers, can be viewed as n 2 -<br />

tuples <strong>of</strong> real numbers with coordinate wise addition and<br />

appropriate multiplication obeying the axioms <strong>of</strong> a ring. Our third<br />

n<br />

example consists <strong>of</strong> n − tuples R <strong>of</strong> real numbers with coordinate<br />

wise addition and appropriate multiplication, so that the resulting<br />

system is a (not necessarily commutative) ring. Such systems, <strong>of</strong>ten<br />

extensions <strong>of</strong> the complex numbers.


óØóŠŽ@íØ@ð−bàb÷@<br />

Course Objectives<br />

The main aims <strong>of</strong> the present course are:<br />

1. To introduce the basic concepts <strong>of</strong> group theory and ring theory to<br />

the students and illustrate these concepts by examples.<br />

2. To give the ideas on the nature <strong>of</strong> some problems in group theory<br />

and ring theory and then giving the methods by which one can prove<br />

those problems.<br />

3. The concept <strong>of</strong> a group can be used to explain some geometrical and<br />

physical phenomena, so that there are so many applications <strong>of</strong> group<br />

theory in physics and chemistry and for this reason this subject is<br />

also necessary for physics and chemistry students.<br />

4. Ring theory has been constructed as a trial to abstract some known<br />

properties <strong>of</strong> integers and algebraic numbers, so that these numbers<br />

were (till to now) an important and a suitable area to the ideas on<br />

which the developments <strong>of</strong> ring theory are based.<br />

5. The first part <strong>of</strong> this course consists <strong>of</strong> five chapters. In the first<br />

chapter <strong>of</strong> this course the groups and subgroups are defined and so<br />

many examples <strong>of</strong> them are given to make students so much familiar<br />

with the nature <strong>of</strong> groups. The second chapter deals with some<br />

special types <strong>of</strong> groups and subgroups such as, cyclic groups, simple<br />

groups, symmetric group S n , abelian groups, normal subgroups, the<br />

center <strong>of</strong> the groups, the alternating group A n and the quotient<br />

groups. The third chapter is devoted to study the properties <strong>of</strong><br />

groups and the ability <strong>of</strong> transferring these properties from a group<br />

to an other by a mapping which is known as a group<br />

homomorphism and at the end <strong>of</strong> this chapter some classical<br />

isomorphism theorems are given by which we can determine those<br />

groups which are isomorphic, so that they have exactly the same<br />

algebraic properties. In chapter four, we have presented prime<br />

groups and sylow p − groups and the sylow theorems are given<br />

which help us to know whether a finite group is simple or not and<br />

several examples <strong>of</strong> simple groups at the end <strong>of</strong> this chapter are<br />

given. The last chapter <strong>of</strong> this part deals with indecomposable and<br />

solvable groups. In fact, the concept <strong>of</strong> solvable groups gave the<br />

whole answer to a very old question which is: can we solve every<br />

equation


<strong>of</strong> degree n , for n ≥ 5, by radicals ?.<br />

6. The second part <strong>of</strong> this subject consists <strong>of</strong> eight chapters. In chapter<br />

six and chapter seven we gave the definitions <strong>of</strong> rings, subrings and<br />

ideals and supported with examples. Also, some types <strong>of</strong> rings and<br />

subrings are introduced such as, the center <strong>of</strong> a ring, maximal ideals,<br />

prime ideals, primary and semiprimary ideals and the relationships<br />

between these types <strong>of</strong> ideals are determined and the quotient rings,<br />

ring homomorphisms are studied in chapter eight and at the end <strong>of</strong><br />

this chapter the concept <strong>of</strong> embedding <strong>of</strong> rings are introduced.<br />

Euclidean domains, principal ideal domains, unique factorization<br />

domains, prime elements and irreducible elements all are studied in<br />

chapter nine and chapter ten and some relations between these<br />

integral domains are obtained. In chapter eleven, we defined and<br />

studied polynomial rings and the relations between this type <strong>of</strong> rings<br />

with Euclidean domains, principal ideal domains and unique<br />

factorization domains are determined. Also, irreducible and<br />

primitive polynomials are studied. In chapter twelve, Noetherian<br />

and Artinian rings are studied and the relations between them are<br />

given. The last chapter was devoted for defining the nil radical <strong>of</strong><br />

ideals and some results are proved.


A List <strong>of</strong> Some References:<br />

[1] S. Singh & Qazi Zameeruddin : ” Modern Algebra ” Vikas<br />

Publishing House ( 1972).<br />

[2] V. K. Khanna & S.K.Bhambri : ” A Course in Abstract<br />

Algebra ” Vikas Publishing House (2004).<br />

[3] H. A. Nielsen : ” Elementary Commutative Algebra ”<br />

Department <strong>of</strong> Mathematical Sciences-<strong>University</strong> <strong>of</strong> Aarhus<br />

(2005).<br />

[4] P. Garrett : ”Abstract Algebra-Lectures and Worked Examples<br />

for a Gradate Course ” (2005).<br />

[5] A. Hermann : ” Abstract Algebra ” (2004).

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!