an abstraction belonging to or characteristic of two entities or parts together

a science (or group of related sciences) dealing with the logic of quantity and shape and arrangement

(mathematics) a mathematical relation such that each element of a given set (the domain of the function) is associated with an element of another set (the range of the function)

(mathematics) a relation between a pair of integers: if both integers are odd or both are even they have the same parity; if one is odd and the other is even they have different parity

(logic and mathematics) a relation between three elements such that if it holds between the first and second and it also holds between the second and third it must necessarily hold between the first and third

(logic and mathematics) a relation such that it holds between an element and itself

a statement that two numbers or geometric figures have the same shape and size, or that one has the same shape and size as the mirror image of the other.

a science (or group of related sciences) dealing with the logic of quantity and shape and arrangement