Half-line

The half-line is determined by a number.

x > a

(a, +∞) = {x Pertenece Set of Real Numbers / a < x < +∞}

Half-line

x ≥ a

[a, +∞) = {x Pertenece Set of Real Numbers / a ≤ x < +∞}

x < a

(-∞, a) = {x PerteneceSet of Real Numbers / -∞ < x < a}

x ≤ a

(-∞, a] = {x Pertenece Set of Real Numbers / -∞ < x ≤ a}