Transitivity (mathematics)

In logic and mathematics, transitivity is a property of a binary relation. It is a prerequisite of an equivalence relation and of a partial order.

Definition and examples

In general, given a set with a relation, the relation is transitive if whenever a is related to b and b is related to c, then a is related to c. For example:

• Size is transitive: if A>B and B>C, then A>C.
• Subsets are transitive: if A is a subset of B and B is a subset of C, then A is a subset of C.
• Height is transitive: if Sidney is taller than Casey, and Casey is taller than Jordan, then Sidney is taller than Jordan.
• Rock, paper, scissors is not transitive: rock beats scissors, and scissors beats paper, but rock doesn't beat paper. This is called an intransitive relation.

Given a relation [math]\displaystyle{ R }[/math], the smallest transitive relation containing [math]\displaystyle{ R }[/math] is called the transitive closure of [math]\displaystyle{ R }[/math], and is written as [math]\displaystyle{ R^+ }[/math].

Related pages

• Symmetric relation