EECS 1019 Lecture Notes - Lecture 9: Bijection, Surjective Function

• School: York University
• Department: Electrical Engineering and Computer Science
• Course: EECS 1019
• Professor: John Michael Machacek

Document Summary

Chapter 2: basic structures sets, functions, sequences, sum and matrices. Given two non-empty sets a and b a function f. From a to b is an assignment of exactly 1 element of b to each element of a. The range of f is the set of all images. If f(a) = b then b is called the range of a. And a is called preimage of b f(a) = b, with a a and b b. { f(a): a a} e. g: true or false. Let f: a b is a function and a a and b b. The element a a can have more than 1 image. The element b b can have more than 1 preimage. Functions can be thought of as relations. A relation between sets a and b is just a subset. { (a, f(a) ): a a } a x b e. g: consider the function which maps people to their preferred drinks.