for S being satisfying_CongruenceIdentity satisfying_SegmentConstruction satisfying_BetweennessIdentity satisfying_Pasch TarskiGeometryStruct
for a, b, c being POINT of S st ( Middle a,b,c or between a,b,c ) holds
( Collinear a,b,c & Collinear b,c,a & Collinear c,a,b & Collinear c,b,a & Collinear b,a,c & Collinear a,c,b )