  Here is a direct problem for Sidon sets: Given a linear form $\varphi = c_1
x_1 + \cdots + c_h x_h $, construct and describe sets $A$ that are Sidon sets
for $\varphi$. This paper considers an inverse problem for Sidon sets: Given a
set $A$, determine the linear forms $\varphi$ such that $A$ is a Sidon set for
$\varphi$.
