  H. L. Skala (1992) gave the first elegant first-order axiom system for
hyperbolic geometry by replacing Menger's axiom involving projectivities with
the theorems of Pappus and Desargues for the hyperbolic plane. In so doing,
Skala showed that hyperbolic geometry is incidence geometry. We improve upon
Skala's formulation by doing away with Pappus and Desargues altogether, by
substituting for them two simpler axioms.

Logic;Combinatorics;Metric Geometry