MAT 190 HW #4 due 2/11 Even the very best mathematicians have on occassion claimed to have proved something that later turned out to not be so - their proof had a subtle gap, or there was a simple error in calculation, or they inadvertently assumed something that was not as rock-sold as they had imagined. So, over the centuries, mathematicians have learned to be extremely critical of proofs. Proofs knit the fabric of mathematics together, and if a single thread is weak, the entire fabric may unravel. Ian Stewart

Exercises Complete the following exercises: 2.2 (pp 52-53): 9, 10, 11, 13, 15, 21, 23, 26, 28, 31. 2.3 (pp 63-65): 1, 2, 6.

Reading Read 2.4: Functions and answer the following reading questions: Define and give an example of "partial order" and "total order." Define and give an example of a "function". Identify the domain and codomain of your example function. Define and give an example of a "one-to-one" function and an "onto" function. What is a one-to-one correspondence? Define "composition" of functions and an "inverse" function.