- #1

ehrenfest

- 2,020

- 1

## Homework Statement

My book says that [itex](a,b:a^4=1,b=a^2)[/itex] is a presentation of Z_4. I strongly disagree. If they want to get a presentation of Z_4, they need to get b as a consequence of their relations, but I only see that b^2 is a consequence of their relations. Please confirm that my book is wrong.