Enumeration: inclusion and exclusion, recurrence relations, generating functions and applications. Graph theory: connectivity, planarity, Hamilton paths and Euler trails. Error-correcting codes. Designs and finite geometries. Symmetry and counting. Also listed as MATH 3855.Precludes additional credit for MATH 3805 and MATH 3825. Prerequisite(s): MATH 2100 or a grade of B or higher in MATH 2108 or MATH 3101.Lectures three hours a week and one hour tutorial.