In mathematics, especially order theory, a partially ordered set (or poset) formalizes and generalizes the intuitive concept of an ordering, sequencing, or arrangement of the elements of a set. A poset consists of a set together with a binary relation that indicates that, for certain pairs of elements in the set, one of the elements precedes the other. Such a relation is called a partial order to reflect the fact that not every pair of elements need be related: for some pairs, it may be that neither element precedes the other in the poset. Thus, partial orders generalize the more familiar total orders, in which every pair is related. A finite poset can be visualized through its Hasse diagram, which depicts the ordering relation.
A familiar real-life example of a partially ordered set is a collection of people ordered by genealogical descendancy. Some pairs of people bear the descendant-ancestor relationship, but other pairs bear no such relationship.
Read more about Partially Ordered Set: Formal Definition, Examples, Extrema, Orders On The Cartesian Product of Partially Ordered Sets, Strict and Non-strict Partial Orders, Inverse and Order Dual, Number of Partial Orders, Linear Extension, In Category Theory, Partial Orders in Topological Spaces, Interval
Famous quotes containing the words partially, ordered and/or set:
“There was an Old Man who supposed,
That the street door was partially closed;”
—Edward Lear (1812–1888)
“But one sound always rose above the clamor of busy life and, no matter how much of a tintinnabulation, was never confused and, for a moment lifted everything into an ordered sphere: that of the bells.”
—Johan Huizinga (1872–1945)
“Artists the minute they set up as artists,
Before, that is, they are themselves accepted,
And boys the minute they get out of college.
I can’t help thinking those are tests to go by.”
—Robert Frost (1874–1963)