# Sums of Two and Four Squares

 Title: Sums of Two and Four Squares Author: Roelof Oosterhuis Submission date: 2007-08-12 Abstract: This document presents the mechanised proofs of the following results:any prime number of the form 4m+1 can be written as the sum of two squares;any natural number can be written as the sum of four squares BibTeX: ```@article{SumSquares-AFP, author = {Roelof Oosterhuis}, title = {Sums of Two and Four Squares}, journal = {Archive of Formal Proofs}, month = aug, year = 2007, note = {\url{http://isa-afp.org/entries/SumSquares.html}, Formal proof development}, ISSN = {2150-914x}, }``` License: BSD License