This document discusses concepts related to cardinal utility theory, including: - The definition of utility and assumptions of cardinal utility theory - The concepts of total utility, marginal utility, and the law of diminishing marginal utility - Assumptions of the law of equi-marginal utility and how it relates to consumer equilibrium - Determinants of consumer equilibrium like substitution and income effects from price changes - Indifference curves and how they relate to budget constraints and consumer optimization - The meaning of consumer surplus as the excess utility consumers receive over their total expenditures.