| Relation, in logic, a set of ordered pairs, triples, quadruples, and so on. |
| The first number in the ordered pairs for each outcome is the payoff to the row player, the second number the payoff to the column player. |
| On 4 November 1833 Hamilton read a paper to the Royal Irish Academy expressing complex numbers as algebraic couples, or ordered pairs of real numbers. |
| In addition to his work on geometry, Bolyai developed a rigorous geometric concept of complex numbers as ordered pairs of real numbers. |
| From there analogy was understood as identity of relation between any two ordered pairs, whether of mathematical nature or not. |
| In 1814 Argand had represented the complex numbers as points on the plane, that is as ordered pairs of real numbers. |
