The Guinness Encyclopedia

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Extensible Markup Language | 1995-08-15 | 3KB | 29 lines

<?xml version="1.0" encoding="utf-8" ?> <!DOCTYPE card PUBLIC "-//Apple, Inc.//DTD card V 2.0//EN" "" > <card> <id>43532</id> <filler1>0</filler1> <cantDelete> <false /> </cantDelete> <showPict> <true /> </showPict> <dontSearch> <false /> </dontSearch> <owner>5472</owner> <link rel="stylesheet" type="text/css" href="stylesheet_3106.css" /> <content> <layer>background</layer> <id>25</id> <text>ets and Paradoxes (2 of 7)Union and intersectionWe can use circles to show the relationship between two (or more) sets. Let us suppose that Sue has a brother, Tim, who feeds and looks after the dog and the mouse; he also helps Sue look after the horse. If S is the set of pets looked after by Sue and T is the set of pets looked after by Tim, we can show their responsibilities like this: It is easy to see that the set of all the family pets looked after by the children is {cat, rabbit, horse, dog, mouse}. This is called the union of the two sets, and is written S ┬╗T (we say, 'S union T ').The two sets have a member in common, the horse. The set of members that belong to both of two given sets is known as their intersection; here, it is the set whose only member is the horse. This is written S ┬½T = {horse}. This is a set, even though it has only one member (as far as the family's pets are concerned) and we write 'horse ┼Æ horse', where the symbol '┼Æ' means 'is a member of '.</text> </content> <content> <layer>background</layer> <id>23</id> <text>ΓÇó THE SCIENTIFIC METHODΓÇó CORRESPONDENCE, COUNTING AND INFINITYΓÇó COMPUTERSΓÇó LOGIC</text> </content> <content> <layer>background</layer> <id>36</id> <text>5868334494</text> </content> <name>p066-2</name> <script></script> </card>