The signed circular chromatic number 
of a signed graph
is the infimum of the real numbers 
admitting a map of its vertices
to a circle of circumference 
with circular distance at least 1 across each positive graph edge and at most 
across each negative graph edge
(Naserasr et al. 2021). Circular distance is the shorter arc length. For an
all-positive signed graph with an graph
edge, this agrees with the ordinary circular
chromatic number.
Wang and Zhou (2026) constructed a simple planar signed triangulation on 85 vertices with signed circular chromatic number exactly 5. Their convention interchanges positive and negative edges. Under the convention used here, their example must therefore have all edge signs reversed. Wang and Zhou (2026) report AI assistance with discovering an initial example and checking the mathematical proofs.
