Summary
Starting with the general abstract definition of a relation, the various sorts of order relations are described and defined, illustrated by many examples. The notion of order isomorphism is introduced. Lattices and Boolean algebras are defined. Examples of these are given and some simple properties derived. Section 3.2 is not a prerequisite for later chapters, although there is reference in Chapter 5 to some of its results.
The reader is presumed to have some experience with abstract algebraic ideas. There is no dependence on the results in Chapters 1 and 2, but in some examples ideas from these chapters are used.
Order relations and ordered sets
The notion of a relation is fundamental in mathematics. Like the notion of a set, it is extremely general and consequently it crops up everywhere. We shall start from the beginning, with the broadest definition, but before we do that, let us observe that there are three kinds of relation which are particularly important, namely, functions, equivalence relations and order relations. Every student of mathematics should know what a function is and how central is the role played by functions in all branches of mathematics. Also, equivalence relations should be familiar although they are perhaps less pervasive. The idea of an order relation, as a general notion, is perhaps less well known, since much of mathematics needs to refer only to particular order relations and does not need to use the general notion or its properties.
To save this book to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.