### NSUCRYPTO-2022

### NSUCRYPTO-2020

### NSUCRYPTO-2018

### NSUCRYPTO-2016

# First round 2018

### Section B

### Problem 7 :

### Additional information

- The question should be reformulated as follows: "Prove that the only element in R(r, n)/R(r-1,n), where 0 < r < n, fixed by the action of A is 0".