Binary relationship, relationship set with abbreviated name, and ternary relationship set are the different kinds of sets. A binary relationship in math terms means that there are ordered pairs.
For a set with a finite number, n, of elements, the number of subsets in 2^n. This includes the null set and the set itself. Things get a bit complicated if the original set has infinitely many elements. It is still 2^k but the complications arise because of infinities and transfinite numbers.
A finite set, with n elements has 2n subsets, including the empty set and itself. For infinite sets the number of subsets is the same order of infinity.
Equality is a relationship that can be defined on the elements of a set. Equality holds between two elements that have the same value.
A finite set is one containing a finite number of distinct elements. The elements can be put into a 1-to-1 relationship with a proper subset of counting numbers. An infinite set is one which contains an infinite number of elements.
The difference between joint sets and disjoint sets is the number of elements in common. A disjoint set, in math, does not any elements in common. A joint set must have at least one number in common.
A finite set has a finite number of elements, an infinite set has infinitely many.
The number of elements. A set with n elements has 2n subsets; for example, a set with 5 elements has 25 = 32 subsets.
The number of subjects will depend on what the elements of the set are. The number of subsets is 2a.
The cardinality of a set is the number of elements in the set.
A finite set or a countably infinite set.
The median. If there are an odd number of elements in the set, there is a middle number which is the median. If there are an even number of elements in the set, the median is the mean of the middle two numbers.