*(poritz.net)*

PrefaceThis is a first draft of a free (as in speech, not as in beer) (although it is free as in beer as well) undergraduate number theory textbook. It was used for Math 319 at Colorado State University – Pueblo in the spring semester of 2014. Thanks are hereby offered to the students in that class — Megan Bissell, Tennille Candelaria, Ariana Carlyle, Michael Degraw, Daniel Fisher, Aaron Griffin, Lindsay Harder, Graham Harper, Helen Huang, Daniel Nichols, and Arika Waldrep — who offered many useful suggestions and found numerous typos. I am also grateful to the students in my Math 242 Introduction to Mathematical Programming class in that same spring semester of 2014 — Stephen Ciruli, Jamen Cox, Graham Harper, Joel Kienitz, Matthew Klamm, Christopher Martin, Corey Sullinger, James Todd, and Shelby Whalen — whose various programming projects produced code that I adapted to make some of the figures and examples in the text.The author gratefully acknowledges the work

An Introductory Course in Elementary Number Theoryby Wissam Raji [seewww.saylor.org/books/] from which this was initially adapted. Raji's text was released under the Creative CommonsCC BY 3.0license, seecreativecommons.org/licenses/by/3.0. This work is instead released under aCC BY-SA 4.0license, seecreativecommons.org/licenses/by-sa/4.0. (The difference is that if you build future works off of this one, you must also release your derivative works with a license that allows further remixes over which you have no control.)

via: https://www.poritz.net/jonathan/share/index.html

Hat tip:

be sure to check out the materials that @poritzj has shared at his website, incl. all you wanted to know about cryptography but were afraid to ask:https://t.co/SdxbbNlNsT

Yet Another Introductory Number Theory Textbook (Cryptology Emphasis Version) — CC-licensed! #Domains19 https://t.co/HsWU5gxvmM— Laura Gibbs (@OnlineCrsLady) June 10, 2019