Published online by Cambridge University Press: 10 February 2022
We consider meromorphic solutions of functional-differential equations
\[ f^{(k)}(z)=a(f^{n}\circ g)(z)+bf(z)+c, \]where $n,\,~k$ are two positive integers. Firstly, using an elementary method, we describe the forms of $f$
and $g$
when $f$
is rational and $a(\neq 0)$
, $b$
, $c$
are constants. In addition, by employing Nevanlinna theory, we show that $g$
must be linear when $f$
is transcendental and $a(\neq 0)$
, $b$
, $c$
are polynomials in $\mathbb {C}$
.