theorem Th9: :: FSCIRC_1:9

for x, y, c being non pair set holds
( InputVertices (BorrowStr (x,y,c)) = {x,y,c} & InnerVertices (BorrowStr (x,y,c)) = {[<*x,y*>,and2a],[<*y,c*>,and2],[<*x,c*>,and2a]} \/ {(BorrowOutput (x,y,c))} )