[R] find inflexion point of discrete value list with R

[Jonas Stein]

i have a list of values like this

x y
1 3
2 2
3 3
4 4
5 5
6 4
7 3
8 2
9 3

and need the inflexion points (and all max and min).
Is there a nice way to get the local max, min and inflexion points?

kind regards,

-- 
Jonas Stein <news at jonasstein.de>