The comparability graph of a partially ordered set 
is the graph with vertex set 
for which vertices 
and 
are adjacent iff either 
or 
in 
.
Comparability Graph
See also
Interval Graph, Partially Ordered SetExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Comparability Graph." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/ComparabilityGraph.html