A partially ordered set is defined as an ordered pair 
.
Here, 
is called the ground set of 
and 
is the partial order of 
.
Ground Set
See also
Partial Order, Partially Ordered SetExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Ground Set." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/GroundSet.html