Lecture
This lecture covers the concept of intersection between sets, defined as the subset of elements that belong to both sets. It introduces the notation X∩Y for the intersection of sets X and Y, and explains the properties of intersection, such as being associative and commutative. Examples are provided to illustrate the concept, along with Venn diagrams. The lecture also demonstrates the equality X∩(Y∪Z) = (X∩Y)∪(X∩Z) using the principle of double inclusion. The properties of intersection are compared to properties of multiplication, emphasizing the relationship between set operations and arithmetic operations.