Abstract :
In this paper, we study the existence problem of periodic solutions for the following first-order
nonlinear evolution equation
u (t )+A(t)u(t)+F t,u(t) 0, t∈ R,
u(t + T ) = u(t ), t ∈ R,
in a Hilbert space H, where A is a monotone type operator and F is a nonlinear operator. Existence
results are obtained without assuming the coercivity condition.
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