  Lines and circles pose significant scalability challenges in synthetic
geometry. A line with $n$ points implies ${n \choose 3}$ collinearity atoms, or
alternatively, when lines are represented as functions, equality among ${n
\choose 2}$ different lines. Similarly, a circle with $n$ points implies ${n
\choose 4}$ cocyclicity atoms or equality among ${n \choose 3}$ circumcircles.
We introduce a new mathematical concept of $k$-equivalence relations, which
generalizes equality ($k=1$) and includes both lines ($k=2$) and circles
($k=3$), and present an efficient proof-producing procedure to compute the
closure of a $k$-equivalence relation.
