I am trying questions from Richard Brualdi Introductory Combinatorics and I am unable to think about this question of Exercise 8.6 .
I am studying combinatorices from Richard Brualdi.
Question is ->Let 2n equally spaced points on a circle be chosen. Show that number of ways to join these points in pairs so that resulting n line segments don't intersect equal nth Catalan number.
I was unable to think about the question . So, looked at hints whose image I am posting. (See Question 1 ch8) . I have no question in first 3 lines of hint but I am unable to deduce how the restrictions on choosing Q gives the desired recurrence relation.
Can someone please give hints to get the required recurrence relation with the help of the arguments given in question ?
I shall be really thankful.
