Oscar Levin is a professor at the University of Northern Colorado. He has taught mathematics and computer science at the college level for over 15 years and has won multiple teaching awards. His research studies the interaction between logic and graph theory, and he is an active developer on the PreTeXt project, an open-source authoring system for writing accessible scholarly documents. He earned his Ph.D. in mathematical logic from the University of Connecticut in 2009.

Outside of the classroom, Oscar enjoys entertaining his two brilliant daughters with jaw-dropping magic tricks and hilarious Dad jokes, hiking with his amazing wife, and coming in second-to-last in local pinball tournaments.

0. Introduction and Preliminaries. 0.1. What is Discrete Mathematics?. 0.2. Discrete Structures. 1. Logic and Proofs. 1.1. Mathematical Statements. 1.2. Implications. 1.3. Rules of Logic. 1.4. Proofs. 1.5. Proofs about Discrete Structures. 1.6. Chapter Summary. 2. Graph Theory. 2.1. Problems and Definitions. 2.2. Trees. 2.3. Planar Graphs. 2.4. Euler Trails and Circuits. 2.5. Coloring. 2.6. Relations and Graphs. 2.7. Matching in Bipartite Graphs. 2.8. Chapter Summary. 3. Counting. 3.1. Pascal's Arithmetical Triangle. 3.2. Combining Outcomes. 3.3. Non-Disjoint Outcomes. 3.4. Combinations and Permutations. 3.5. Counting Multisets. 3.6. Combinatorial Proofs. 3.7. Applications to Probability. 3.8. Advanced Counting Using PIE. 3.9. Chapter Summary. 4. Sequences. 4.1. Describing Sequences. 4.2. Rate of Growth. 4.3. Polynomial Sequences. 4.4. Exponential Sequences. 4.5. Proof by Induction. 4.6. Strong Induction. 4.7. Chapter Summary. 5. Discrete Structures Revisited. 5.1. Sets. 5.2. Functions. 6. Additional Topics. 6.1. Generating Functions. 6.2. Introduction to Number Theory.