let n be Nat; :: thesis: for C being Simple_closed_curve

for i, j, k being Nat st 1 < i & i < len (Gauge (C,n)) & 1 <= j & j <= k & k <= width (Gauge (C,n)) & n > 0 & (Gauge (C,n)) * (i,k) in Upper_Arc (L~ (Cage (C,n))) & (Gauge (C,n)) * (i,j) in Lower_Arc (L~ (Cage (C,n))) holds

LSeg (((Gauge (C,n)) * (i,j)),((Gauge (C,n)) * (i,k))) meets Lower_Arc C

let C be Simple_closed_curve; :: thesis: for i, j, k being Nat st 1 < i & i < len (Gauge (C,n)) & 1 <= j & j <= k & k <= width (Gauge (C,n)) & n > 0 & (Gauge (C,n)) * (i,k) in Upper_Arc (L~ (Cage (C,n))) & (Gauge (C,n)) * (i,j) in Lower_Arc (L~ (Cage (C,n))) holds

LSeg (((Gauge (C,n)) * (i,j)),((Gauge (C,n)) * (i,k))) meets Lower_Arc C

let i, j, k be Nat; :: thesis: ( 1 < i & i < len (Gauge (C,n)) & 1 <= j & j <= k & k <= width (Gauge (C,n)) & n > 0 & (Gauge (C,n)) * (i,k) in Upper_Arc (L~ (Cage (C,n))) & (Gauge (C,n)) * (i,j) in Lower_Arc (L~ (Cage (C,n))) implies LSeg (((Gauge (C,n)) * (i,j)),((Gauge (C,n)) * (i,k))) meets Lower_Arc C )

assume that

A1: 1 < i and

A2: i < len (Gauge (C,n)) and

A3: 1 <= j and

A4: j <= k and

A5: k <= width (Gauge (C,n)) and

A6: n > 0 and

A7: (Gauge (C,n)) * (i,k) in Upper_Arc (L~ (Cage (C,n))) and

A8: (Gauge (C,n)) * (i,j) in Lower_Arc (L~ (Cage (C,n))) ; :: thesis: LSeg (((Gauge (C,n)) * (i,j)),((Gauge (C,n)) * (i,k))) meets Lower_Arc C

A9: L~ (Lower_Seq (C,n)) = Lower_Arc (L~ (Cage (C,n))) by A6, JORDAN1G:56;

L~ (Upper_Seq (C,n)) = Upper_Arc (L~ (Cage (C,n))) by A6, JORDAN1G:55;

hence LSeg (((Gauge (C,n)) * (i,j)),((Gauge (C,n)) * (i,k))) meets Lower_Arc C by A1, A2, A3, A4, A5, A7, A8, A9, Th21; :: thesis: verum

for i, j, k being Nat st 1 < i & i < len (Gauge (C,n)) & 1 <= j & j <= k & k <= width (Gauge (C,n)) & n > 0 & (Gauge (C,n)) * (i,k) in Upper_Arc (L~ (Cage (C,n))) & (Gauge (C,n)) * (i,j) in Lower_Arc (L~ (Cage (C,n))) holds

LSeg (((Gauge (C,n)) * (i,j)),((Gauge (C,n)) * (i,k))) meets Lower_Arc C

let C be Simple_closed_curve; :: thesis: for i, j, k being Nat st 1 < i & i < len (Gauge (C,n)) & 1 <= j & j <= k & k <= width (Gauge (C,n)) & n > 0 & (Gauge (C,n)) * (i,k) in Upper_Arc (L~ (Cage (C,n))) & (Gauge (C,n)) * (i,j) in Lower_Arc (L~ (Cage (C,n))) holds

LSeg (((Gauge (C,n)) * (i,j)),((Gauge (C,n)) * (i,k))) meets Lower_Arc C

let i, j, k be Nat; :: thesis: ( 1 < i & i < len (Gauge (C,n)) & 1 <= j & j <= k & k <= width (Gauge (C,n)) & n > 0 & (Gauge (C,n)) * (i,k) in Upper_Arc (L~ (Cage (C,n))) & (Gauge (C,n)) * (i,j) in Lower_Arc (L~ (Cage (C,n))) implies LSeg (((Gauge (C,n)) * (i,j)),((Gauge (C,n)) * (i,k))) meets Lower_Arc C )

assume that

A1: 1 < i and

A2: i < len (Gauge (C,n)) and

A3: 1 <= j and

A4: j <= k and

A5: k <= width (Gauge (C,n)) and

A6: n > 0 and

A7: (Gauge (C,n)) * (i,k) in Upper_Arc (L~ (Cage (C,n))) and

A8: (Gauge (C,n)) * (i,j) in Lower_Arc (L~ (Cage (C,n))) ; :: thesis: LSeg (((Gauge (C,n)) * (i,j)),((Gauge (C,n)) * (i,k))) meets Lower_Arc C

A9: L~ (Lower_Seq (C,n)) = Lower_Arc (L~ (Cage (C,n))) by A6, JORDAN1G:56;

L~ (Upper_Seq (C,n)) = Upper_Arc (L~ (Cage (C,n))) by A6, JORDAN1G:55;

hence LSeg (((Gauge (C,n)) * (i,j)),((Gauge (C,n)) * (i,k))) meets Lower_Arc C by A1, A2, A3, A4, A5, A7, A8, A9, Th21; :: thesis: verum