Sets, relations and functions, sequences, sums, cardinality of sets richard mayr university of edinburgh, uk richard mayr university of edinburgh, uk discrete mathematics. This course will roughly cover the following topics and speci c applications in computer science. A relation can be informally thought of as a property which either holds or does not hold between. A set is a collection of objects, called elements of the set.
Duplicates dont contribute anythi ng new to a set, so remove them. Basic concepts of set theory, functions and relations. A binary relation from a to b is a subset of the cartesian product a. Introduction sets are one of the basic building blocks for the types of objects considered in discrete mathematics important for counting programming languages have set operations set theory is an important branch of mathematics many different systems of axioms have been used to develop set theory here we are not concerned with a formal set of axioms for.
For each ordered pair x, y in the relation r, there will be a directed edge from the vertex x to vertex y. I this is why bijections are also calledinvertible functions instructor. If a and b are two sets, then the following results hold true. Relations and functions 3 definition 4 a relation r in a set a is said to be an equivalence relation if r is reflexive, symmetric and transitive. Notice that a function maps values to one and only one value. A binary relation r from set x to y written as xry or rx, y is a subset of the cartesian product x. Functions and binary relations functions are special kinds of binary relations. This site is based on the class lectures and discussions on discrete mathematics. To impart the mathematical concepts and numerical methods required to computer science. We began discussing this topic in the last chapter when we introduced equivalence relations. The set s is called the domain of the relation and the set t the codomain. The overflow blog how the pandemic changed traffic trends from 400m visitors across 172 stack. A set a is said to be a proper subset of b if and only.
Discrete mathematicsdiscrete mathematics and itsand its applicationsapplications seventh editionseventh edition chapter 9chapter 9 relationsrelations lecture slides by adil aslamlecture slides by adil aslam mailto. Be very comfortable with functions and the notions of injectivity, surjectivity, bijectivity. Sets denote the collection of ordered elements whereas relations and functions defines the operations performed on sets the relations defines the connection between the two given sets. Induction functions graphs the pigeonhole principle relations logic set theory cardinality these are the building blocks we will use throughout the rest of the quarter. Discrete mathematicsset theorypage 2 wikibooks, open.
Combinatorics, graph theory, the idea of function, recurrence relations, permutations, and set theory are all part of discrete math. Discrete mathematics lecture notes, yale university, spring 1999 l. Browse other questions tagged functions discretemathematics relations or ask your own question. The relations defines the connection between the two given sets. Technology which is discrete mathematics 4th ed, ross, k. This alone assures the subject of a place prominent in human culture. Sets, relations and functions, sequences, sums, cardinality of sets. Whenever sets are being discussed, the relationship between the elements of the sets is the next thing that comes up. The order of the elements in a set doesnt contribute. Mar 17, 2011 discrete mathematics relations and functions 1. Number theory athe math behind the rsa crypto system. Sets, logic, relations, and functions andrew kay september 28, 2014 abstract this is an introductory text, not a comprehensive study. Some parts are loosely adapted from the discrete computing and algorithms and software engineering modules on the bsc computer. A relation is any association or link between elements of one set, called the domain or less formally the set of inputs, and another set, called the range or set of outputs.
Mathematics stack exchange is a question and answer site for people studying math at any level and professionals in related fields. Sets, relations and functions are the tools that help to perform logical and mathematical operations on mathematical and other realworld entities. As an introduction to discrete mathematics, this text provides a straightforward overview of the range of mathematical techniques available to students. Set operations include set union, set intersection, set difference, complement of set, and cartesian product. A relation can be represented using a directed graph. Vesztergombi parts of these lecture notes are based on l. A function is a relationship between two sets of numbers. Mathematics introduction and types of relations geeksforgeeks. A set a is said to be a proper subset of b if and only if a b and a b. If anybody could help me out with them and explain, id greatly appreciate it. We now present three simple examples to illustrate this.
Learners will become familiar with a broad range of mathematical objects like sets, functions, relations, graphs, that are omnipresent in computer science. Discrete mathematicsfunctions and relations wikibooks. Sequences and series are among the most important applications of. Discrete mathematics the past four weeks have focused exclusively on discrete mathematics. We denote that a is a proper subset of b with the notation a b. Nov 25, 2016 chapter 9 relations in discrete mathematics 1. Problems on discrete mathematics1 ltex at january 11, 2007. Direct and inverse image of a set under a relation. Two sets are equal if and only if they have the same elements. Ideas of mathematical logic, concepts of set theory and boolean algebra. Discrete mathematics sets and functions pangyen weng, ph. Basic definitions and concepts of sets, relations and.
I just started working with functions in my discrete mathematics class and we got presented with these two problems to think about at home. Basic concepts of set theory, functions and relations 1. Some people mistakenly refer to the range as the codomain range, but as we will see, that really means. All functions are relations but not all relations are functions. P kubelka an incomplete list of things to know 2 i inverse images of subsets of bunder a function. Discrete mathematics uses a range of techniques, some of which is seldom found in its continuous counterpart. The symbol a,b denotes the set that contains just the elements a and b. Here you can download the free lecture notes of discrete mathematics pdf notes dm notes pdf materials with multiple file links to download. Discrete mathematics c marcin sydow properties equivalence relation order relation nary relations contents binaryrelation domain,codomain,image,preimage.
Types of functions floor and ceiling functions an interesting result 2. After number and its use in computation, the notion of function, usually expressed in terms of a symbolic formula, is probably the. Sets, relations, and functions introduction sets relations functions summary problems find, read and cite all the. Functions on the set of natural numbers historical note the fibonacci sequence calculate earlier terms.
Assuming very little prior knowledge, and with the minimum of technical complication, it gives an account of the foundations of modern mathematics. Problems on discrete mathematics1 chungchih li2 kishan mehrotra3 syracuse university, new york latex at january 11, 2007 part i 1no part of this book can be reproduced without permission from the authors. A function defined on sets a,b a b assigns to each element in the domain set a exactly one element from b. The greatest common divisor of a and a is jaj, which is most often not equal to 1. Modern science and contemporary western culture are unthinkable without highlevel mathematics. Cse 1400 applied discrete mathematics relations and. Discrete mathematics relations and functions mathematics. Notes on abstract algebra university of southern mississippi. Sets, relations, functions introduction basic objects in. Basic building block for types of objects in discrete mathematics. A binary relation from a to b is a subset of a cartesian product a x b. Cse 1400 applied discrete mathematics relations and functions. Relational ideas have become more important with the advent of computer science and the rise of discrete mathematics, however. The elements of a set may be discrete or continuous.
Discrete structures provide a tool box in computer science. Example 2 let t be the set of all triangles in a plane with r a relation in t given by r t 1, t 2. Two values in one set could map to one value, but one value must never map to two values. This chapter will be devoted to understanding set theory, relations, functions.
What is the difference between a relation and a function from a to b. Venn diagram, invented in 1880 by john venn, is a schematic diagram that shows all possible logical relations between different mathematical sets. Ling 310, adapted from umass ling 409, partee lecture notes. Sets denote the collection of ordered elements whereas relations and functions defines the operations performed on sets. A good reference beyond this summary is the text for the course mathematics for information. To get a 10, we would needa 9 and a 8, for which we would need a 7 and a 6,etc. Even functions even functions have line symmetry about the yaxis. Sets, relations, functions introduction basic objects.
For two distinct set, a and b with cardinalities m and n, the maximum cardinality of the relation r from a to b is mn. To know the fundamental ide as of mathematical logic, concepts of set theory and boolean algebra uniti. Binary relations a binary relation r between the sets s and t is a subset of the cartesian product s. A thats what we must end up with do change just one part of the expression at a time, using just one of the set laws at a time dont miss steps out, and change two things at once. Introduction sets relations functions summary problems. The discrete mathematics notes pdf dm notes pdf book starts with the topics covering logic and proof, strong induction,pigeon hole principle, isolated vertex, directed graph, alebric structers. R tle a x b means r is a set of ordered pairs of the form a,b where a a and b b. Many contemporary mathematical applications involve binary or nary relations in addition to computations. I find the domain of a realvalued function when youre. Discrete math concerns counting, probability, sophisticated forms of addition, and limit processes over discrete sets. But even more, set theory is the milieu in which mathematics takes place today. This article examines the concepts of a function and a relation. Relations and its types concepts are one of the important topics of set theory.
Discrete mathematics functions 2846 useful properties of floor and ceiling functions 1. The greatest common divisor of a and a is jaj, which is most often not equal to. Cantors diagonal argument to show the reals are uncountable. Discrete mathematics lecture 10 sets, functions, and relations. Set theory is a basis of modern mathematics, and notions of set theory are used in all. Discrete structures for computer science ruoming jin mw 2. The text covers the mathematical concepts that students will encounter in many disciplines such as computer science, engineering, business, and the sciences. Inverse functions i every bijection from set a to set b also has aninverse function i the inverse of bijection f, written f 1, is the function that assigns to b 2 b a unique element a 2 a such that fa b i observe. George voutsadakis lssu discrete structures for computer science august 2018 20 66.
Discrete mathematics sets relations mathematics stack. This book is designed for a one semester course in discrete mathematics for sophomore or junior level students. Many different systems of axioms have been proposed. Quantitative modes of thinking, mathematical ideas, algorithmic techniques, and symbolic reasoning permeate the way we conceptualize and interact with the world today. In contrast, for ordered pairs, the order of the elements matters. The set s is called the domain of the relation and the set. A binary relation r on a single set a is defined as a subset of axa. Discrete mathematics relations whenever sets are being discussed, the. Hauskrecht relations and functions relations represent one to many relationships between elements in a and b.
Induction functions graphs the pigeonhole principle relations logic set theory cardinality these are the building blocks we will use throughout the rest of the. Sets, relations and functions, sequences, sums, cardinality of sets richard mayr university of edinburgh, uk. Discrete mathematics c marcin sydow properties equivalence relation order relation nary relations discretemathematics relations cmarcinsydow. Relations and functions mathematics relations a relation is a set of ordered pairs, usually defined by some sort of rule. Sets, relations and functions all three are interlinked topics. Besides reading the book, students are strongly encouraged to do all the. Relations and functions in mathematics pdf determine which of the relations define y as a function of x. Sets help in distinguishing the groups of certain kind of objects. The number of vertices in the graph is equal to the number of elements in the set from which the relation has been defined. August 4 and 6, 2009 our main goal is here is to do counting using functions. Relations may exist between objects of the same set or between objects of two or more sets. Lectures 6 and 7 sets, relations, functions and counting instructor.
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