let S be satisfying_Tarski-model TarskiPlane ; :: thesis: for a, b being POINT of S st between a,b,a holds
a = b
let a, b be POINT of S; :: thesis: ( between a,b,a implies a = b )
S is satisfying_BetweennessIdentity ;
hence ( between a,b,a implies a = b ) ; :: thesis: verum