A study of solutions for an elliptic problem with critical growth in the gradient
Elliptic equations, critical growth, indefinite problem, Mountain Pass Theorem, lower and
upper solutions
In this work, we study the solutions for the problem
− ∆u = c(x)u + ⎸∇u⎹
2
+ f(x), u ∈ H
0
1
(Ω) ∩ L
∞
(Ω),
in which Ω is a bounded domain of R , and , for some . Firstly,
N N ≥ 3 c, f ∈ L
q
(Ω) q >
N
2
based on Jeanjean and Quoirin (2016), we suppose c is allowed to change sign, c , ,
+≢ 0 f ≩ 0
μ > 0 constant, and, using a lower semicontinuity argument together with the Mountain Pass
Theorem, we find two distinct solutions for our problem. Then, based on De Coster and Fernández
(2020), supposing c ≨ 0 and μ > 0 constant, we find a necessary and sufficient condition such
that our problem has a solution. Finally, using the lower and upper solutions method, we show the
existence of solutions is kept when μ ∈ L .