set of numbers
metaclass of sets of numbers
set of non-negative integers
the set of positive integers and zero
extended real number line
extension of the reals by +∞ and −∞
set of positive integers
set of integers greater than 0
complex unit circle
set of complex numbers whose absolute value is equal 1; Lie group of complex numbers of unit modulus; topologically a circle
projectively extended real line
extension of the set of the real numbers by a point denoted ∞
set of real numbers
set whose elements are the real numbers