The Existence Of Non-extreme Solution Of Three-dimensional Differential Systems

The three-dimensional di?erential systemis considered under the assumptions thatλi (i = 1, 2, 3) are positive constants and ai(t)(i = 1, 2, 3) are positive continuous functions on [0,∞). If the system satisfiesThen, the necessary and su?cient conditions are established for the existence of non-extreme solution of (S), which exists on infinite intervals with the form [T,∞), T≥0.