Two planar sets are circularly separable if there exists a circle enclosing
one of the sets and whose open interior disk does not intersect the other
set. This paper studies two problems related to circular separability. A li
near-time algorithm is proposed to decide if two polygons are circularly se
parable. The algorithm outputs the smallest separating circle. The second p
roblem asks for the largest circle included in a preprocessed, convex polyg
on, under some point and/or line constraints. The resulting circle must con
tain the query points and it must lie in the halfplanes delimited by the qu
ery lines.