theorem Th13: :: WAYBEL35:13

for L being RelStr
for C being set
for R being auxiliary(i) Relation of L st R satisfies_SIC_on C holds
for x, z being Element of L st x in C & z in C & [x,z] in R & x <> z holds
ex y being Element of L st
( y in C & [x,y] in R & [y,z] in R & x < y )