theorem
  (ex x,y being Element of AS st x<>y) & (for x,y,z,t,u,w being Element
of AS holds x,y // y,x & x,y // z,z & (x<>y & x,y // z,t & x,y // u,w implies z
  ,t // u,w) & (x,y // x,z implies y,x // y,z)) & (ex x,y,z being Element of AS
st not x,y // x,z) & (for x,y,z being Element of AS ex t being Element of AS st
x,z // y,t & y<>t) & (for x,y,z being Element of AS ex t being Element of AS st
x,y // z,t & x,z // y,t) & (for x,y,z,t being Element of AS st z,x // x,t & x<>
z ex u being Element of AS st y,x // x,u & y,z // t,u) iff AS is AffinSpace by
