MathDB

1399

points and some chords between them is given.

a)

In every step we can take two chords

RS,PQ

with a common point other than

P,Q,R,S

and erase exactly one of

RS,PQ

and draw

PS,PR,QS,QR

let

s

be the minimum of chords after some steps. Find the maximum of

s

over all initial positions.

b)

In every step we can take two chords

RS,PQ

with a common point other than

P,Q,R,S

and erase both of

RS,PQ

and draw

PS,PR,QS,QR

let

s

be the minimum of chords after some steps. Find the maximum of

s

over all initial positions.
Proposed by Afrouz Jabalameli, Abolfazl Asadi

3