let MP be OrtAfSp; :: thesis: for a, b, c being Element of MP st not LIN a,b,c holds
( a <> b & b <> c & a <> c )
let a, b, c be Element of MP; :: thesis: ( not LIN a,b,c implies ( a <> b & b <> c & a <> c ) )
assume A1:
not LIN a,b,c
; :: thesis: ( a <> b & b <> c & a <> c )
assume A2:
( not a <> b or not b <> c or not a <> c )
; :: thesis: contradiction
reconsider b' = b, a' = a, c' = c as Element of (Af MP) by ANALMETR:47;
LIN a',b',c'
by A2, AFF_1:16;
hence
contradiction
by A1, ANALMETR:55; :: thesis: verum