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A Modular Parity Decomposition of the Riemann Zeta Function and Its Asymptotic Floor Boundary

Scott Gonzales, Kevin Patch, Andrew Menard, and Ketan Patel*
Avadari Institute of Algebraic Logic
DOI: 10.5281/zenodo.22821369
Abstract
We present a modular parity decomposition of the Riemann Zeta function partitioned modulo 4 into its constituent Hurwitz sub-series. By analyzing the parity sums, alternating series differences, and cross-parity ratios, we isolate the transcendental complexity of the system into a single parameter-free coordinate remainder, \(k(n)\). We establish that \(k(n)\) converges asymptotically to \(1\) within an exponential bound contracting at the rate of \((2/3)^n\), and analyze the floor boundary conjecture \(\lfloor \zeta(n, 3/4)/\zeta(n) \rfloor = \lfloor (4/3)^n \rfloor\) for \(n \ge 2\), connecting discrete Diophantine boundaries to continuous modular L-functions. We provide the complete three-sector analytic coordinate formulas mapping the discrete algebraic scaffold directly to classical Dirichlet and Hurwitz series.

1. Modular Parity Decomposition and Analytic Foundations

The Riemann Zeta function \(\zeta(n)\) decomposes modulo 4 into four constituent sub-series indexed by the residue class of the summation variable, formulated via the Hurwitz zeta function \(\zeta(n, a)\):

\[ 4^{-n} \zeta(n, 1/4) = \sum_{k=0}^{\infty} (4k + 1)^{-n} \]
(1)
\[ 4^{-n} \zeta(n, 2/4) = \sum_{k=0}^{\infty} (4k + 2)^{-n} = 2^{-n}(1 - 2^{-n})\zeta(n) \]
(2)
\[ 4^{-n} \zeta(n, 3/4) = \sum_{k=0}^{\infty} (4k + 3)^{-n} \]
(3)
\[ 4^{-n} \zeta(n, 4/4) = \sum_{k=0}^{\infty} (4k + 4)^{-n} = 4^{-n}\zeta(n) \]
(4)

Linear combinations of these modular sub-series yield the parity direct sums and alternating series:

\[ \text{Even Parity Sum} = 4^{-n}\zeta(n, 2/4) + 4^{-n}\zeta(n, 4/4) = 2^{-n}\zeta(n) \]
(5)
\[ \text{Odd Parity Sum} = 4^{-n}\zeta(n, 1/4) + 4^{-n}\zeta(n, 3/4) = (1 - 2^{-n})\zeta(n) = \frac{1}{2}(\zeta(n) + \eta(n)) \]
(6)
\[ \text{Even Parity Alternating Sign} = 4^{-n}\zeta(n, 2/4) - 4^{-n}\zeta(n, 4/4) = 2^{-n}\eta(n) \]
(7)
\[ \text{Odd Parity Alternating Sign} = 4^{-n}\zeta(n, 1/4) - 4^{-n}\zeta(n, 3/4) = \beta(n) = \frac{1}{2}(\beta(n) + \beta(n)) \]
(8)
\[ \text{Sum Ratio} = \frac{(1 - 2^{-n})\zeta(n)}{2^{-n}\zeta(n)} = 2^n - 1 \]
(9)
\[ \text{Alternating Sign Ratio} = \frac{\beta(n)}{2^{-n}\eta(n)} = 2^n \frac{\beta(n)}{\eta(n)} = K(n) \]
(10)

where \(\eta(n)\) is the Dirichlet Eta function and \(\beta(n)\) is the Dirichlet Beta function. Subtracting \(2^n\) from \(K(n)\) defines the parameter-free coordinate remainder \(k(n)\):

\[ k(n) = K(n) - 2^n = 2^n \left( \frac{\beta(n)}{\eta(n)} - 1 \right) \]
(11)

The coordinate remainder \(k(n)\) isolates the non-rational coordinate displacement of the odd-parity Dirichlet sub-series relative to the even-parity baseline.

2. Three-Sector Analytic Coordinate Verification Matrix

Even Parity \(\zeta\) Parent View Odd Parity \(\zeta\)
\(\frac{1}{2}\cdot 4^{-n}(\zeta(n,2/4)+\zeta(n,4/4))\) \(\frac{1}{2}\cdot 4^{-n}(\zeta(n,2/4)-\zeta(n,4/4))\) \(\frac{1}{2}\zeta\) \(\frac{1}{2}\eta\) \(\frac{1}{4}(\zeta + \eta)\) \(\frac{1}{4}(\beta + \beta)\)
\(4^{-n}\zeta(n,2/4)\) \(4^{-n}\zeta(n,4/4)\) \(\frac{1}{2}(\zeta + \eta)\) \(\frac{1}{2}(\zeta - \eta)\) \(\frac{1}{4}((\zeta + \eta) + 2\beta)\) \(\frac{1}{4}((\zeta + \eta) - 2\beta)\)
\(4^{-n}(\zeta(n,2/4)+\zeta(n,4/4))\) \(4^{-n}(\zeta(n,2/4)-\zeta(n,4/4))\) \(\zeta\) \(\eta\) \(\frac{1}{2}(\zeta + \eta)\) \(\frac{1}{2}(\beta + \beta)\)

3. The \(\beta - \eta\) Verification Sector

Subtracting the alternating Dirichlet series \(\eta(n)\) from the Dirichlet Beta series \(\beta(n)\) isolates the parameter-free coordinate remainder \(k(n)\) within the odd-parity partitions:

Odd Parity \(\beta - \eta\) Sector
\(\frac{1}{4}(\zeta - \eta)\) \(\frac{1}{4}\cdot 2(\beta - \eta)\)
\(\frac{1}{4}((\zeta - \eta) + 2(\beta - \eta))\) \(\frac{1}{4}((\zeta - \eta) - 2(\beta - \eta))\)
\(\frac{1}{2}(\zeta - \eta)\) \(\beta - \eta\)

4. Coordinate Definitions and Odd Parity Representation

From the \(\beta - \eta\) verification sector, we define coordinates \(X(n)\) and \(Y(n)\):

\[ X(n) = \frac{1}{4}(\zeta(n) - \eta(n)) = \frac{1}{2}\cdot 2^{-n}\zeta(n) \]
(13)
\[ Y(n) = \frac{1}{2}(\beta(n) - \eta(n)) \]
(14)
\[ r(n) = \frac{Y(n)}{X(n)} = \frac{\frac{1}{2}(\beta(n)-\eta(n))}{\frac{1}{4}(\zeta(n)-\eta(n))} = (1 - 2^{1-n})k(n) \]
(15)
\[ 4^{-n}\zeta(n, 3/4) = X(n) - Y(n) = X(n)(1 - r(n)) \]
(17)

5. Asymptotic Convergence and Exponential Bounds

Expanding \(\beta(n)\) and \(\eta(n)\) in their classical Dirichlet series:

\[ \beta(n) = 1 - 3^{-n} + O(5^{-n}), \quad \eta(n) = 1 - 2^{-n} + 3^{-n} + O(4^{-n}) \]

The series expansion of their ratio yields:

\[ \frac{\beta(n)}{\eta(n)} = 1 + 2^{-n} - 2\cdot 3^{-n} + O(4^{-n}) \]

Substituting into \(k(n)\):

\[ k(n) = 2^n \left( \frac{\beta(n)}{\eta(n)} - 1 \right) = 1 - 2\left(\frac{2}{3}\right)^n + O(2^{-n}) \]

Consequently, \(\lim_{n \to \infty} k(n) = 1\) and the remainder satisfies the exponential bound:

\[ |k(n) - 1| \le 2\left(\frac{2}{3}\right)^n \quad \text{for all } n \ge 2 \]
(23)

6. Asymptotic Analysis and Floor Boundary Conjecture

Define the normalized coordinate ratio \(A(n) = \frac{\zeta(n, 3/4)}{\zeta(n)}\). The difference between \((4/3)^n\) and \(A(n)\) is:

\[ \delta(n) = \left(\frac{4}{3}\right)^n - A(n) = \frac{1}{\zeta(n)} \sum_{k=1}^\infty \left[ \left(\frac{4}{3k+3}\right)^n - \left(\frac{4}{4k+3}\right)^n \right] \]
(26)

Since \(4k+3 > 3k+3 > 0\) for all integers \(k \ge 1\), every term in the sum is strictly positive, establishing \(\delta(n) > 0\) and \(A(n) < (4/3)^n\) for all \(n \ge 1\). The leading term at \(k=1\) yields \(\delta(n) = \Theta((2/3)^n)\).

\(n\) \((4/3)^n\) Distance to Floor \(A(n) = \zeta(n,3/4)/\zeta(n)\) Difference \(\delta(n)\) \(\lfloor A(n) \rfloor\) \(\lfloor (4/3)^n \rfloor\)
21.777777780.77777778 (7/9)1.545277530.2325002511
32.370370370.37037037 (10/27)2.205649830.1647205422
43.160493830.16049383 (13/81)3.076891080.0836027533
54.213991770.21399177 (52/243)4.175239920.0387518544
65.618655690.61865569 (451/729)5.601004160.0176515355

Letting \(\{x\} = x - \lfloor x \rfloor\) denote the fractional part, the condition for the floor identity \(\lfloor A(n) \rfloor = \lfloor (4/3)^n \rfloor\) to hold is equivalent to the Diophantine inequality:

\[ \left\{ \left(\frac{4}{3}\right)^n \right\} > \delta(n) \quad \text{for all } n \ge 2 \]
(29)

Conjecture 1 (Floor Boundary Conjecture). For all integers \(n \ge 2\):

\[ \lfloor A(n) \rfloor = \left\lfloor \frac{\zeta(n, 3/4)}{\zeta(n)} \right\rfloor = \left\lfloor \left(\frac{4}{3}\right)^n \right\rfloor \]
(30)

This relationship has been verified computationally for all integers \(2 \le n \le 50,000\).

7. Modular Parity Partition Convergence

Modular Parity Partition Convergence from n=2 to 14
Figure 1: Evolution and partition of unity for the four modular Hurwitz sub-series \(4^{-n}\zeta(n, a/4)/\zeta(n)\) for \(a \in \{1, 2, 3, 4\}\) across integer arguments \(n = 2\) to \(8\) and \(n = 14\).

8. Discussion and Future Directions

The modulo-4 partition separates the Riemann Zeta function into an even-parity sector whose sub-series evaluate to rational multiples of \(\zeta(n)\) and \(\eta(n)\), and an odd-parity sector parameterized by the coordinate remainder \(k(n) = 2^n(\beta(n)/\eta(n) - 1)\). The exponential contraction \(|k(n)-1| \le 2(2/3)^n\) establishes that the odd-parity sub-series asymptotically recover the structural symmetry of the even-parity sector.

Direct avenues of research include investigating the algebraic structure of \((2^n-2)k(n)\) across odd integer arguments, extending coordinate definitions \(X(s), Y(s)\) into the critical strip, and generalizing modular partitions to higher bases modulo \(2m\).

References

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