cograph

Noun

 * 1)  A graph formed from another by complementation and disjoin union.
 * 2)  The dual of the graph of a function. It is an ordinate-indexed partition of the disjoint union of the set of abscissas and ordinates of the function.
 * Given a function whose graph is $$\{(1,7), (2,5), (3,3), (4,3), (5,2), (6,4), (7,6), (8,5), (9,7), (10,6), (11,6)\}$$, append an apostrophe to the abscissas so that they will not be confused with ordinates when obtaining their disjoint union, which is: $$\{2, 3, 4, 5, 6, 7, 1', 2', 3', 4', 5', 6', 7', 8', 9', 10', 11'\}$$. The cograph then is $$\{\{7,1',9'\}, \{6, 7', 10', 11'\}, \{5, 2', 8'\}, \{4, 6'\}, \{3, 3', 4'\}, \{2, 5'\}\}$$.

Derived terms

 * cographic