U(n) Group Examples: Are They Cyclic Groups or Not?

The group of units modulo n, U(n), under multiplication mod n, is an Abelian group for any positive integer n greater than 1. Sometimes U(n) is a cyclic group and sometimes U(n) is not a cyclic group. We consider the examples U(16), U(20), and U(18) by computing the orders of their elements to see if these groups have generators or not. If U(n) has a generator, then it is cyclic. If U(n) does not have a generator, then it is not cyclic.    • Abstract Algebra Course, Lecture 1: Introd...  . 🔴 Joe Gallian's Abstract Algebra textbook: https://amzn.to/4boQZcy 🔴 Abstract Algebra Course Lectures Playlist:    • Abstract (Modern) Algebra Course Lectures   🔴 Number Theory Examples and Proofs Playlist:    • Number Theory Examples and Proofs   🔴 Abstract Algebra Exam 1 Review:    • Abstract Algebra Exam 1 Review Problems an...   #AbstractAlgebra #GroupTheory #CyclicGroup #GroupOfUnits #ModularArithmetic Links and resources =============================== 🔴 Subscribe to Bill Kinney Math: https://www.youtube.com/user/billkinn... 🔴 Subscribe to my Math Blog, Infinity is Really Big: https://infinityisreallybig.com/ 🔴 Follow me on Twitter:   / billkinneymath   🔴 Follow me on Instagram:   / billkinneymath   🔴 You can support me by buying "Infinite Powers, How Calculus Reveals the Secrets of the Universe", by Steven Strogatz, or anything else you want to buy, starting from this link: https://amzn.to/3eXEmuA. 🔴 Check out my artist son Tyler Kinney's website: https://www.tylertkinney.co/ 🔴 Desiring God website: https://www.desiringgod.org/ AMAZON ASSOCIATE As an Amazon Associate I earn from qualifying purchases.