“…and consider the new system associated to (u (1) , v (1) ). For F, G ∈ C 1 , we have (u(x, t; 0), v(x, t; 0)) = (0, 0), so ∂ t u (1) (x, t) − µ∆u (1) (x, t) = 0 and ∂ t v (1) (x, t) − ν∆v (1) (x, t) = β 10 (x, t)u (1) (x, t) + β 01 (x, t)v (1) (x, t).…”