let x, y be set ; :: thesis: for M being Pnet holds
( ( [x,y] in Flow M & x in the carrier' of M implies ( not x in the carrier of M & not y in the carrier' of M & y in the carrier of M ) ) & ( [x,y] in Flow M & y in the carrier' of M implies ( not y in the carrier of M & not x in the carrier' of M & x in the carrier of M ) ) & ( [x,y] in Flow M & x in the carrier of M implies ( not y in the carrier of M & not x in the carrier' of M & y in the carrier' of M ) ) & ( [x,y] in Flow M & y in the carrier of M implies ( not x in the carrier of M & not y in the carrier' of M & x in the carrier' of M ) ) )
let M be Pnet; :: thesis: ( ( [x,y] in Flow M & x in the carrier' of M implies ( not x in the carrier of M & not y in the carrier' of M & y in the carrier of M ) ) & ( [x,y] in Flow M & y in the carrier' of M implies ( not y in the carrier of M & not x in the carrier' of M & x in the carrier of M ) ) & ( [x,y] in Flow M & x in the carrier of M implies ( not y in the carrier of M & not x in the carrier' of M & y in the carrier' of M ) ) & ( [x,y] in Flow M & y in the carrier of M implies ( not x in the carrier of M & not y in the carrier' of M & x in the carrier' of M ) ) )
A1: the carrier of M misses the carrier' of M by NET_1:def 2;
Flow M c= [:the carrier of M,the carrier' of M:] \/ [:the carrier' of M,the carrier of M:] by NET_1:def 2;
hence ( ( [x,y] in Flow M & x in the carrier' of M implies ( not x in the carrier of M & not y in the carrier' of M & y in the carrier of M ) ) & ( [x,y] in Flow M & y in the carrier' of M implies ( not y in the carrier of M & not x in the carrier' of M & x in the carrier of M ) ) & ( [x,y] in Flow M & x in the carrier of M implies ( not y in the carrier of M & not x in the carrier' of M & y in the carrier' of M ) ) & ( [x,y] in Flow M & y in the carrier of M implies ( not x in the carrier of M & not y in the carrier' of M & x in the carrier' of M ) ) ) by A1, SYSREL:22; :: thesis: verum