The plan for today is to take some pain medicine, finish packing, and watch at least one good movie. I may try to go for a run, as the half marathon is less than a month away, but weâll see how Iâm feeling later. The moral of the story is: Iâm happy. Iâm ready.
Extensional definition. An extensional definition of a concept or term formulates its meaning by specifying its extension, that is, every object that falls under the definition of the concept or term in question.
When we define a set, if we take pieces of that set, we can form what is called a subset. So for example, we have the set {1, 2, 3, 4, 5}. A subset of this is {1, 2, 3}. Another subset is {3, 4} or even another, {1}. However, {1, 6} is not a subset, since it contains an element (6) which is not in the parent set.hen our sets included integers. The universal set for that would be all the integers. In fact, when doing Number Theory, this is almost always what the universal set is, as Number Theory is simply the study of integers.