Lecture
This lecture covers fundamental concepts in mathematical analysis, focusing on norms and distances. The instructor begins by introducing the definitions and properties of norms, emphasizing positivity, homogeneity, and the triangle inequality. The discussion progresses to distances, defined as the norm of the difference between two points, and explores their properties, including symmetry and the triangle inequality. The lecture also delves into open and closed sets, explaining how to determine whether a set is open or closed based on its boundary. The instructor illustrates these concepts with examples, demonstrating how to visualize sets in a two-dimensional space. The importance of understanding the boundary of a set is highlighted, as it plays a crucial role in classifying sets as open or closed. The lecture concludes with a discussion on the interior and closure of sets, providing a comprehensive overview of these essential topics in analysis.