1.2: Basic Set Operations
Even as set members are discrete, so are sets themselves. The question we ask about each member is, "Of what sets is it entirely a member?" Although there are no partial set memberships, an entity can be entirely a member of more than one set. So, we can perform various operations on sets, such as add one set to another and subtract one set from another. With questions that require a Yes or No response, there is no dual membership since those are on the same hierarchical level. However, with layered hierarchies, dual 100% membership is possible. For example, we can talk about a car that is also a vehicle. The entity exists entirely in two different sets. Later in the course, we will talk more about hierarchies.
Read this page to become familiar with the various types of sets. This page is an aid to set terminology and notation.