Assertion: triangle | /r/DefinedAs | the lines of reflection
Facets:
Source sentences:
text: Triangle groups preserve a tiling by triangles, namely a fundamental domain for the action (the triangle defined by the lines of reflection), called a Möbius triangle, and are given by a triple of integers, (l,m,n), – integers correspond to (2l,2m,2n) triangles coming together at a vertex.