In stability theory, hyperstability is a property of a system that requires the state vector to remain bounded if the inputs are restricted to belonging to a subset of the set of all possible inputs. In stability theory, hyperstability is a property of a system that requires the state vector to remain bounded if the inputs are restricted to belonging to a subset of the set of all possible inputs. Definition: A system is hyperstable if there are two constants k 1 ≥ 0 , k 2 ≥ 0 {displaystyle k_{1}geq 0,k_{2}geq 0} such that any state trajectory of the system satisfies the inequality: