This lecture covers the fundamentals of digital systems with a focus on integral theorems. The instructor discusses iterated integrals, explaining their definitions and applications in various contexts. The lecture begins with an introduction to theorems related to iterated integrals, emphasizing the importance of continuous functions. The instructor illustrates the process of calculating integrals over defined regions, using examples to demonstrate the application of Fubini's theorem. The discussion includes the evaluation of double integrals and the interchange of integration order, highlighting that the results remain consistent regardless of the order of integration. The lecture also delves into the concept of measure theory, defining null sets and their properties. The instructor explains how to handle collections of null sets and their implications in higher dimensions. Overall, the lecture provides a comprehensive overview of integral calculus within the framework of digital systems, equipping students with essential tools for further study in the field.