A formula for connecting two algebraic expressions with an inequality symbol. The relationship between numbers in the formula is not all equal signs, but inequalities. For example, 2x+2y≥2xy, sinx≤ 1, ex >；; 0

Connected inequalities are called strict inequalities, and inequalities connected by not less than sign (greater than or equal to sign), not greater than sign (less than or equal to sign) ≥ and ≤ are called non-strict inequalities or generalized inequalities.