Math 2001
Introduction to Discrete Mathematics


Spring 2022

Please see below for lecture summaries, homework and other study material. For your grades, please see Canvas.

Date Topics
Jan.10. Basic definitions and notation about sets. Notes.
Jan.12. Cartesian products of sets. Power sets. Notes.
Homework 1 (due Wed., Jan. 19): 1.1: 3, 12, 18, 29, 31; 1.2: 9, 15; 1.3: 13, 14, 15; 1.4: 14, 15.
Jan.14. Cardinalities of power sets. Set unions, intersections, differences and complements. Notes.
Jan.17. Martin Luther King Holiday, no class.
Jan.19. Using Venn diagrams. Proofs of set equalities. Notes.
Homework 2 (due Wed., Jan. 26): 1.5: 2, 6, 10; 1.6: 2, 4, 6; 1.7: 4, 10; 1.8: 2, 4, 8, 14.
Jan.21. Indexed sets. Statements. "And", "or", and "not" operators. Notes.
Jan.24. Conditional statements. How to prove various types of statements. Logical equivalences. Notes.
Jan.26. DeMorgan's Law for logic. From logic to sets. Open sentences and quantifiers. Notes.
Homework 3 (due Wed., Feb. 2): 2.1: 2, 4, 10; 2.4: 1, 4, 5; 2.6: 2, 3, 12. 2.7: 4, 8.
Jan.28. The multiplication, addition, and subtraction principles for counting. Example problems. Notes.
Jan.31. Practice problems. Factorials. Permutations vs combinations. Notes.
Feb.02. Class cancelled due to inclement weather.
Feb.04. Binomial coefficients. Combinatorial identities. Pascal's triangle. Notes.
Homework 4 (due Wed., Feb. 9): 3.3: 2, 4, 8, 10; 3.4: 3, 10, 12; 3.5: 4, 6, 10, 12, 18.
Feb.07. The binomial theorem and its applications. Another combinatorial identity. Notes.
Feb.09. The inclusion-exclusion principle. Notes.
Homework 5 (due Wed., Feb. 16): 3.6: 3, 7, 12; 3.7: 2, 4, 6, 8; 3.8: 2, 4, 6, 8. 10.
Feb.11. Worksheet on permutations and combinations.. (Solutions)
Feb.14. Multisets. The bars-and-stars method. Notes
Feb.16. More bars-and-stars problems. The word problem (permutations of multisets). Notes.
Homework 6 (due Wed., Feb. 23): 3.8: 5, 7, 9, 11, 13, 14; 3.9: 2, 4; 3.10: 5, 6.
Feb.18. Summary of counting problem types. The pigeonhole principle. Notes.
Feb.21. The division principle. Combinatorial proofs. Notes.
Worksheet on counting problems involving multisets (Solutions). Topics for Midterm I.
Feb.23. More on combinatorial proofs. Homework discussion. List of midterm topics. Notes.
No homework due next week.
Feb.25. Midterm 1.
Feb.28. Direct proofs of conditional statements. Case discussions. Notes.
Mar.02. More direct proofs. Worksheet on direct proofs. Notes.
Homework 7 (due Wed., Mar. 09): Chapter 4: 4, 10, 13, 16, 20, 26; Chapter 5: 6, 10, 15, 20.
Mar.04. Congruence of integers. Contrapositive proofs. Notes.
Mar.07. Proof by contradiction. Recommendations for mathematical writing. Notes.
Mar.09. The proof that there are infinitely many primes. Notes. Second worksheet on proofs.
Homework 8 (due Wed., Mar. 16): Chapter 5: 4, 9, 12, 28; Chapter 6: 8, 9, 10, 14, 15.
Mar.11. Proofs of equivalences and some non-conditional statements. Notes.
Mar.16. GCDs and the Euclidean algorithm. Constructive vs. non-constructive proofs. Notes.
Homework 9 (due Wed., Mar. 30): Chapter 7: 6, 12, 13, 23, 26, 31, 32, 33. Chapter 8: 2, 19, 28.
Mar.18. More proof examples from Chapter 7. Proofs of set containments. Notes.
Mar.28. Proofs of set equalities. Disproofs and counter-examples. Notes.
Mar.30. More disproofs. Notes. Third worksheet on proofs.
No homework due next week.
Apr.01. Midterm 2.
Apr.04. Proof by mathematical inductions: strategy and examples. Notes.
Apr.06. More proofs by induction. Introduction to strong mathematical induction. Notes.
Homework 10 (due Wed. Apr. 13): Chapter 10: 2, 8, 15, 16, 18, 19, 20.
Apr.08. More strong induction proofs. Graphs and trees. Notes.
Apr.11. More recursions and inductions: the fundamental theorem of arithmetic, Fibonacci numbers. Notes.
Apr.13. More on the Fibonacci sequence. Notes. Worksheet on (strong) mathematical induction.
Homework 11 (due Wed. Apr. 20): Chapter 10: 6, 21, 23, 24, 26, 30, 42.
Apr.15. Discussion for the induction worksheet. Notes.
Apr.18. Relations. Reflexivity, symmetry and transitivity. Equivalence relations. Notes.
Apr.20. Proofs verifying a relation is an equivalence relation. Homework discussion. Notes.
Homework 12 (due Wed. Apr. 27): 11.1: 2, 4, 8; 11.2: 4, 8, 15; 11.3: 4, 8.
Apr.22. Partitions from equivalence relations. Notes.
Apr.25. Basic notions and proofs regarding functions. Notes.
Apr.27. Review for final exam. Notes.