cograph

co- +‎ graph

cograph (plural cographs)

1. (mathematics) A graph formed from another by complementation and disjoin union
2. (mathematics) 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'}}.

• cographic