Echo waves in the linearly coupled Oregonators

This paper gives the conditions of existence of echo wave and the accurate expression of the relative period in the coupled Oregonators and finds that in this system there are two types of echo waves,one of which satisfies th e pretty relations x(1)(t) + x(2)(t) = 2u(+), z(1)(t) + z(2)(t) = 2 u(+) (w here u(+) is a component of the homogeneous positive steady state of the sy stem).