let A be Subset of (TOP-REAL 2); :: thesis: for p1, p2, q being Point of (TOP-REAL 2) st A is_an_arc_of p1,p2 & q in A holds
q in L_Segment A,p1,p2,q
let p1, p2, q be Point of (TOP-REAL 2); :: thesis: ( A is_an_arc_of p1,p2 & q in A implies q in L_Segment A,p1,p2,q )
A1:
L_Segment A,p1,p2,q = { q1 where q1 is Point of (TOP-REAL 2) : LE q1,q,A,p1,p2 }
by JORDAN6:def 3;
assume
( A is_an_arc_of p1,p2 & q in A )
; :: thesis: q in L_Segment A,p1,p2,q
then
LE q,q,A,p1,p2
by JORDAN5C:9;
hence
q in L_Segment A,p1,p2,q
by A1; :: thesis: verum