For any positive definite rational quadratic form
of
variables let
denote the graph
with vertices
and
connected
if and only if
.
This notion generalises standard Euclidean distance graphs. In this article we study
these graphs and show how to find the exact value of clique number of the
.
We also prove rational analogue of the Beckman–Quarles theorem that any unit-preserving
bijection of
onto itself is an isometry.