A formula which counts the number of fixed points for a topological transformation.
Lefschetz Trace Formula
See also
Lefschetz Fixed Point TheoremExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Lefschetz Trace Formula." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/LefschetzTraceFormula.html