Oscillator with a detent escapement

An oscillator comprising a resonator of the inertia-elasticity type cooperating with a detent escapement comprising a detent cooperating with an escape wheel, wherein the resonator is in one-piece and comprises an inertia member and a first flexible structure providing the elasticity and forming a virtual pivot axis of the resonator, wherein the detent is in one-piece and comprises a body forming a locking-stone cooperating with the escape wheel, a second flexible structure forming a virtual pivot axis of the detent and an unlocking spring cooperating with a stop member formed at one end of the body of the detent and wherein the inertia member forms an impulse-pallet cooperating with the escape wheel and a discharging-pallet cooperating with the unlocking spring.