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arXiv math/0611300math.NTmath.CO
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Ramanujan恒等式与整数的二次和四次二次型表示

Ramanujan's Identities and Representation of Integers by Certain Binary and Quaternary Quadratic Forms

Alexander Berkovich, Hamza Yesilyurt

摘要:

我们重温了费马和欧拉关于用二进制二次型x^2+5y^2表示整数的老理论。利用Ramanujan的1阶求和公式,建立了\sum_{n,m=-\infty}^{\infty} q^{n^2+5m^2}的一个新的Lambert级数恒等式.费马和欧拉的猜想很容易遵循这个新公式。但我们不会就此止步。采用各种公式中发现拉马努金的笔记本电脑和使用有点巧妙我们obtaina收集新的朗伯系列的某些无穷乘积与二次型,如x^2+6y^2,2x^2+3y^2,x^2+15y^2,3x^2+5y^2,x^2+27y^2,x^2+5(y^2+ z^2+ w^2),5x^2+y^2+ z^2+ w^2。在这个过程中,我们发现了许多新的乘性η-子,并确定了它们的系数。

英文摘要:

We revisit old conjectures of Fermat and Euler regarding representation of integers by binary quadratic form x^2+5y^2. Making use of Ramanujan's_1ψ_1 summation formula we establish a new Lambert series identity for \sum_{n,m=-\infty}^{\infty} q^{n^2+5m^2}. Conjectures of Fermat and Euler are shown to follow easily from this new formula. But we don't stop there. Employing various formulas found in Ramanujan's notebooks and using a bit of ingenuity we obtaina collection of new Lambert series for certain infinite products associated with quadratic forms such as x^2+6y^2, 2x^2+3y^2, x^2+15y^2, 3x^2+5y^2, x^2+27y^2, x^2+5(y^2+ z^2+ w^2), 5x^2+y^2+ z^2+ w^2. In the process, we find many new multiplicative eta-quotients and determine their coefficients.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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