EN
By a sub-super solution argument, we study the existence of positive solutions for the system
⎧$-Δ_{p}u = a₁(x)F₁(x,u,v)$ in Ω,
⎪$-Δ_{q}v = a₂(x)F₂(x,u,v)$ in Ω,
⎨u,v > 0 in Ω,
⎩u = v = 0 on ∂Ω,
where Ω is a bounded domain in $ℝ^{N}$ with smooth boundary or $Ω = ℝ^{N}$. A nonexistence result is obtained for radially symmetric solutions.