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arXiv · 1801.03134

A $q$-analog of Jacobi's two squares formula and its applications

José Manuel Rodríguez Caballero
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Abstract

We consider a $q$-analog $r_2(n, q)$ of the number of representations of an integer as a sum of two squares $r_2(n)$. This $q$-analog is generated by the expansion of a product that was studied by Kronecker and Jordan. We generalize Jacobi's two squares formula from $r_2(n)$ to $r_2(n, q)$. We characterize the signs in the coefficients of $r_2(n, q)$ using the prime factors of $n$. We use $r_2(n, q)$ to characterize the integers which are the length of the hypotenuse of a primitive Pythagorean triangle.

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José Manuel Rodríguez Caballero. 2018-01-09. A $q$-analog of Jacobi's two squares formula and its applications. https://arxiv.org/abs/1801.03134

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