Complete classification of sufficiently large equilateral tilings
Prove that, for every non-reptile and non-commensurate tiling of a triangle T by a triangle R=(a,b,c) having an angle equal to 2π/3, the possible tile counts are exactly the values m^2ab for integers m at least M=3⌈(c^2−a−b)/(ab)⌉.
References
For all non-reptile and non-commensurate tilings of $T$ into $R = (a,b,c)$ with an angle equal to $2\pi/3$, the possible $N$ is the set $${m2 ab | m \geq M} $$ where $M$ is defined as in Theorem~(i).
— Tiling Triangles with $2π/3$ Angles
(2512.22696 - Zhang, 27 Dec 2025) in Conjecture 2, Section 3.1, Equilateral Triangles