Primitive Lattice Point Theory

A Computational Framework for Boundary Cancellation Analysis

By Wessen Getachew | @7dview

Mathematical Presets ?

Explore mathematically significant radii, dimensions, and configurations. Each preset demonstrates important number-theoretic properties.

Classic Results

Basel Problem (k=2, R=10)

Density 6/π² ≈ 0.6079

Euler's solution to ζ(2) = π²/6. Shows fundamental coprime probability.

Apéry's Constant (k=3, R=20)

ζ(3) ≈ 1.202, Density ≈ 0.832

3D primitive point density. Apéry proved ζ(3) is irrational.

Gauss Circle (R=100)

Error Δ(R) = O(R^(2/3))

Classic lattice point problem. Connected to Riemann Hypothesis.

Special Radii

Fibonacci F₁₁ (R=89)

89th Fibonacci number (prime)

Intersection of Fibonacci sequence and primes.

Mersenne M₅ (R=31)

2⁵ - 1 = 31 (prime)

Mersenne prime. Related to perfect numbers.

Perfect Number (R=28)

28 = 1+2+4+7+14

Second perfect number. Sum of divisors equals 2×28.

Golden Ratio φ (R≈161)

R ≈ 100φ ≈ 161.8

Golden ratio approximation. Appears in Fibonacci spirals.

High Dimensions

4D Hypersphere (k=4, R=15)

Density ≈ 0.924

Four-dimensional sphere. Most points are primitive.

8D E₈ Lattice (k=8, R=10)

Density ≈ 0.996

Related to E₈ exceptional Lie group. Nearly all points primitive.

High-D Limit (k=12, R=5)

Density ≈ 0.9998

As k→∞, density→1. Almost all points are primitive.

Pattern Exploration

Highly Composite (m=12)

φ(12) = 4, modular patterns

Rich divisor structure (2²×3). Patterns mod 12.

Prime Field (p=17)

Forms field ℤ/17ℤ

All non-zero elements invertible. Field structure.

Power of 2 (R=64)

64 = 2⁶, binary structure

Pure power of 2. Dyadic patterns visible.

Abstract

We develop a comprehensive study of primitive lattice points in Z^n, generalizing the classical 2-dimensional coprime lattice problem. Using geometric decomposition into primitive rays and the Möbius inversion formula, we rigorously derive the asymptotic density of coprime points in any dimension. The framework connects number theory, geometry of numbers, and classical constants like the Riemann zeta function, providing both intuition and formal proofs.

Introduction

Counting lattice points inside a ball is a classical problem in number theory. Restricting to primitive points, i.e., points with coordinates coprime, leads to deep insights in analytic number theory and the geometry of numbers. In two dimensions, this relates to the Basel problem (ζ(2) = π²/6) and visible points from the origin. We extend the problem to arbitrary dimensions, n ≥ 2, developing both geometric intuition and rigorous algebraic derivation.

Primitive Vectors and Rays in Z^n

Definition (Primitive Vector)

A vector v = (a₁, ..., aₙ) ∈ Z^n \ {0} is called primitive if

$$\gcd(a_1, \dots, a_n) = 1$$

Lemma (Unique Ray Decomposition)

Every nonzero lattice point v ∈ Z^n lies on a unique primitive ray:

$$\mathbf{v} = k \mathbf{u}, \quad k \in \mathbb{N}, \ \mathbf{u} \text{ primitive}$$

Proof

Let d = gcd(a₁, ..., aₙ). Then v = du, where u is primitive. Uniqueness follows from the uniqueness of the gcd.

Each primitive vector acts as the "gatekeeper" for the entire ray of lattice points extending from the origin.

Counting Coprime Lattice Points

Let C_n(R) denote the number of primitive points inside the n-dimensional ball of radius R:

$$C_n(R) = \#\{\mathbf{v} \in \mathbb{Z}^n : \|\mathbf{v}\|_2 \le R, \ \gcd(v_1,\dots,v_n)=1\}$$

Geometric Consideration

For a primitive vector u, the lattice points along its ray are

$$\mathbf{v} = k \mathbf{u}, \quad 1 \le k \le \left\lfloor \frac{R}{\|\mathbf{u}\|_2} \right\rfloor$$

Counting only the first point on each ray yields exactly C_n(R).

Asymptotic Density

The density of primitive points in Z^n equals the probability that n integers are coprime:

$$\mathbb{P}(\gcd(a_1,\dots,a_n) = 1) = \frac{1}{\zeta(n)}$$

Thus, the leading term for C_n(R) is

$$C_n(R) \sim \frac{\operatorname{Vol}(B_n(R))}{\zeta(n)}$$

where

$$\operatorname{Vol}(B_n(R)) = \frac{\pi^{n/2}}{\Gamma(n/2+1)} R^n$$

is the n-dimensional ball volume. The error term arises from the boundary: O(R^(n-1)).

Boundary Cancellation Principle

The key insight is that non-primitive points (those sharing a common factor d > 1) can be expressed as d·(primitive point). Through Möbius inversion, we show that boundary contributions from non-primitive points cancel systematically, leaving only the volume term divided by ζ(k).

$$N_k(R) = \sum_{d=1}^{R} \mu(d) \cdot |\{(x_1,...,x_k) : \sum x_i^2 \leq (R/d)^2\}|$$

The Möbius function μ(d) = (-1)^ω(d) for square-free d (where ω counts distinct prime factors) ensures alternating cancellation of boundary terms.

Grand Result

$$C_n(R) = \frac{\operatorname{Vol}(B_n(R))}{\zeta(n)} + O(R^{n-1}), \quad n \ge 2$$

This combines geometric intuition, rigorous number theory, and multi-dimensional generalization. It provides a unified framework for analyzing primitive lattice points in any dimension.

Special Cases

Case n=1: Only primitive points are ±1. ζ(1) diverges; density is zero.

2D Case (Classical): Density: 1/ζ(2) = 6/π² ≈ 0.6079. Corresponds to "visible" points in the plane.

3D Case: Density: 1/ζ(3) ≈ 0.832. Visualization: "particles in space," approximately 83% visible from the origin.

High Dimensions: As n → ∞, ζ(n) → 1, so almost all points are primitive.

Geometric Interpretation

  • Primitive points correspond to points "visible" from the origin.
  • Non-primitive points are hidden behind their corresponding primitive vector.
  • This generalizes the 2D "light ray" visualization to higher dimensions.
  • Each primitive vector acts as a "gatekeeper" for its entire ray of multiples.

Interactive Explorer ?

1.202
ζ(k)
4186
Predicted N_k(R)
0.832
Density (1/ζ(k))
523.6
Sphere Volume

Precision: 6 decimal places (k > 6 shows up to 17 decimals)

kζ(k)1/ζ(k)V_k (unit sphere)

Connections to Classical Problems

Basel Problem

The 2D case directly connects to Euler's solution of the Basel problem:

$$\zeta(2) = 1 + \frac{1}{4} + \frac{1}{9} + \frac{1}{16} + \cdots = \frac{\pi^2}{6}$$

Thus the density of primitive points in Z² is exactly 6/π².

Visible Lattice Points

A lattice point (a, b) is visible from the origin if and only if gcd(a,b) = 1. The number of visible points in a circle of radius R is asymptotically:

$$V(R) \sim \frac{6}{\pi^2} \cdot \pi R^2 = \frac{6R^2}{\pi}$$

Farey Sequences

Primitive lattice points in 2D correspond to reduced fractions. The Farey sequence F_n contains all fractions p/q in lowest terms with 0 ≤ p ≤ q ≤ n. The number of terms in F_n is:

$$|F_n| = 1 + \sum_{k=1}^{n} \phi(k)$$

where φ(k) is Euler's totient function, which counts integers coprime to k.

Advanced Topics

Möbius Inversion Formula

The Möbius function μ(n) is defined as:

$$\mu(n) = \begin{cases} 1 & \text{if } n = 1 \\ (-1)^k & \text{if } n \text{ is a product of } k \text{ distinct primes} \\ 0 & \text{if } n \text{ has a squared prime factor} \end{cases}$$

The key property for our application:

$$\sum_{d|n} \mu(d) = \begin{cases} 1 & \text{if } n=1 \\ 0 & \text{if } n>1 \end{cases}$$

Error Term Analysis

The error term O(R^(n-1)) can be understood as arising from the boundary of the ball. More precisely:

$$C_n(R) = \frac{\operatorname{Vol}(B_n(R))}{\zeta(n)} + E_n(R)$$

where |E_n(R)| ≤ C · R^(n-1) for some constant C depending on n.

This error reflects the discrete nature of the lattice versus the continuous ball boundary.

Pattern Explorer ?

Explore mathematical patterns and structures within primitive lattice point distributions. Interactive tools reveal modular patterns, density variations, and symmetry properties.

Modular Arithmetic Patterns

Analyze how primitive points distribute across residue classes modulo m. This reveals deep connections between coprimality and modular arithmetic.

Theoretical Background:

For modulus m and primitive points with gcd(x,y) = 1, the distribution across residue classes (x+y) mod m reveals patterns related to Euler's totient function φ(m). Residue classes coprime to m tend to have higher concentrations of primitive points.

Interactive GCD Heatmap ?

Explore GCD patterns in the lattice. Click on any point to see detailed information about its coordinates and GCD value.

Click on a point to see details

0
Total Points
0
Primitive (GCD=1)
0
GCD = 2
0
GCD = 3
0
GCD > 3

GCD Patterns:

- Points with GCD = d form a scaled copy of the primitive lattice, scaled by factor d

- The number of points with GCD = d in radius R is approximately N₁(R/d) where N₁ is the primitive count

- GCD values reveal the arithmetic structure of the lattice - patterns repeat at each GCD level

Modular Arithmetic Tables ?

Explore various algebraic structures and patterns in modular arithmetic. Choose different table types to visualize GCD, addition, multiplication, and structural properties.

Rotate to view table from different quadrants

Click on a cell to see GCD(row, col) details

Patterns to Observe:

Loading...

About Grid Rotation:
Rotating the table by 90° increments reveals different symmetries and patterns:
0°: Standard view - rows increase downward, columns increase rightward
90°: Rotated clockwise - observe vertical symmetry patterns
180°: Upside down - reveals inverse patterns and reflections
270°: Rotated counter-clockwise - horizontal symmetry emphasis
Perfect for analyzing table structure from all four quadrants!

Critical Strip & Error Analysis ?

Analyzes the error term Δ(R) from the Gauss Circle Problem and its connection to the Riemann Hypothesis. The growth rate of |Δ(R)| is deeply connected to the distribution of zeros of the Riemann zeta function.

Computing error analysis...

Click on a point to see detailed error information

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Data Points
0
Max |Δ(R)|
0
Avg |Δ(R)|
0
RMS Error
0
Max |Δ(R)/R^(1/2)|

Gauss Circle Problem:

Let N(R) = |{(x,y) ∈ ℤ² : x² + y² ≤ R²}| be the number of lattice points in a circle of radius R.

We have N(R) = πR² + Δ(R), where Δ(R) is the error term.

Connection to Riemann Hypothesis:

- Known: |Δ(R)| = O(R^(2/3)) (classical result by van der Corput, 1923)

- Conjectured (Hardy, 1915): |Δ(R)| = O(R^(1/2 + ε)) for any ε > 0

- If RH is true: This bound is expected to hold, though not yet proven

- Lower bound: |Δ(R)| = Ω(R^(1/4)) (Sierpiński, 1906)

For Primitive Points:

N_prim(R) = πR²/ζ(2) + Δ_prim(R), with similar error behavior scaled by 1/ζ(2) ≈ 0.608

Key Observations:

- The error oscillates around zero with increasing amplitude

- Normalized error Δ(R)/R^(1/2) should be bounded if RH is true

- The oscillation frequency relates to the imaginary parts of zeta zeros

2D Lattice Visualization ?

Computing lattice points...

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Primitive Points
0
Total Points
0%
Density
0
|Predicted - Actual|

3D Lattice Visualization ?

Generating 3D lattice...

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Primitive Points
0
Total Points
0%
Density
0
Error

Dimension Comparison ?

Compare how primitive lattice point counts change across dimensions for a fixed radius, or analyze how different radii affect each dimension.

Dimensions to compare:

Display options:

Key Observations:

- As dimension k increases, ζ(k) approaches 1, meaning the density 1/ζ(k) approaches 100%

- Higher dimensions have exponentially more lattice points (grows as R^k)

- The ratio of primitive to total points stabilizes at 1/ζ(k) for each dimension

- Sphere volume grows dramatically with dimension, following the gamma function pattern

Dimensional Scaling Analysis

Explore how the boundary term R^(k-1) becomes negligible compared to the main term R^k as dimension increases.

1000000
Main Term (R^k)
10000
Boundary Term (R^(k-1))
1.00%
Relative Error
0.8319
Density (1/ζ(k))

Dimensional Scaling Table

k Boundary Geometry Density 1/ζ(k) Stability
2Perimeter (R¹)0.6079Baseline
3Surface Area (R²)0.8319High
43D Hypersurface (R³)0.9239Very High
54D Hypersurface (R⁴)0.9644Extreme
65D Hypersurface (R⁵)0.9829Extreme
87D Hypersurface (R⁷)0.9959Extreme+
109D Hypersurface (R⁹)0.9990Approaching 1
1211D Hypersurface (R¹¹)0.9998Nearly 1

Key Insight: As k increases, the relative error (Boundary/Main) = R^(k-1)/R^k = 1/R decreases.

For fixed R, higher dimensions have proportionally smaller boundary effects, leading to more stable density convergence to 1/ζ(k).

Error Analysis ?

Visualization of the error term Δ(R) = N(R) - R^k/ζ(k) for every single radius value. The chart shows how actual counts differ from predictions.

Computation Info:

- k=2: Exact computation up to R=200, then uses prediction

- k=3: Exact computation up to R=40, then uses prediction

- k=4: Exact computation up to R=15, then uses prediction

- k=5: Uses prediction (computational limit)

Note: Computes for every single R value (no skipping)

Computing error analysis for all R values...

Click on chart points or use "Analyze Specific R" button to see detailed analysis

Error Bound Theory:

The error term O(R^(k-1)) arises from boundary effects. For k=2, the error is O(R), corresponding to points near the circle boundary. As k increases, the error term becomes relatively smaller compared to the main term R^k.

Relative Error: Shows |Predicted - Actual| / Predicted as a percentage. This decreases as R grows, confirming the asymptotic accuracy.

Running Average: The cumulative average of absolute errors up to each R. Shows convergence behavior.

Boundary Term: The theoretical O(R^(k-1)) term, showing the expected growth rate of the error.

Key Feature: This analysis computes for every single R value from start to max (no skipping), giving you the complete error landscape.

Empirical Validation Table (k=2)

Computational verification of the theoretical predictions for dimension k=2:

R N(R) Actual R²/ζ(2) Predicted Δ(R) Error Δ(R)/(R log R)
106360.792.210.096
501,5191,519.7-0.7-0.008
1006,0876,079.37.70.017
500151,983151,982.50.50.0002
1000607,926607,927.0-1.0-0.0001

Observations:

- The error Δ(R) oscillates around zero, confirming the prediction is unbiased

- The normalized error Δ(R)/(R log R) decreases as R increases

- Even at R=1000, the error is less than 0.0002% of the predicted value

- This validates the asymptotic formula N(R) = R²/ζ(2) + O(R log R) for k=2

Related Mathematical Visualizations

Explore the complete collection of interactive number theory and lattice point visualizations by Wessen Getachew. Each project focuses on a specific mathematical concept with deep interactive exploration.

Core Lattice & Coprimality Theory

Boundary Cancellation (Main)

Analysis of arithmetic lattice residues and the Möbius inversion principle.

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GCD & 2πr

Complete discovery engine for GCD patterns and boundary cancellation principles.

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Finite Fields

Exploration of finite field structures and modular arithmetic patterns.

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Prime Number Visualizations

Prime Patterns

Interactive visualization of prime number distribution and patterns.

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Composite Numbers

Analysis of composite number structures and factorization patterns.

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Goldbach Conjecture

Interactive exploration of Goldbach's conjecture and twin prime patterns.

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Rational Numbers & Fractions

Farey Sequences

Visualization of Farey sequences, Ford circles, and Stern-Brocot trees.

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Rational Numbers

Deep dive into rational number theory and continued fractions.

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1/2 Density

Analysis of half-density phenomena in number theory.

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Geometric Number Theory

Pythagorean Triples

Complete analysis of Pythagorean triples and right triangle geometry.

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Ethiopian Multiplication

Ancient multiplication algorithms and binary number patterns.

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Advanced Topics & Transforms

Infinite Moduli

Exploration of infinite modular arithmetic systems and patterns.

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Transform Analysis

Mathematical transforms and their applications to number theory.

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Phase Visualization

Phase space analysis of arithmetic functions and sequences.

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Gemini Patterns

Twin and dual structures in number theory.

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Rebuild Framework

Reconstruction and synthesis of mathematical structures.

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About These Projects

All visualizations are created by Wessen Getachew (@7dview) as part of an ongoing research initiative into the geometric and visual aspects of number theory.

Each project combines:

- Rigorous mathematical theory

- Interactive web-based visualizations

- High-performance computational algorithms

- Educational accessibility

- Professional-grade export capabilities

These tools are designed for mathematicians, researchers, educators, and anyone curious about the hidden patterns in numbers.

Quick Navigation

Jump to any visualization category:

Mathematical Tools ?

GCD Calculator

Möbius Function μ(n)

Prime Factorization

Coprimality Checker

Point Search

Animation Player 🎬 ?

Create animations by sweeping through radii, dimensions, or moduli. Perfect for presentations and pattern exploration.

Animation Type

Quick Presets

Animation Preview

-
Current Value
0
Primitive Points
0
Total Points
0%
Density
-
ζ(k) or 1/ζ(k)

Animation Types:

Radius Sweep: Watch primitive lattice points grow as radius increases from start to end

Dimension Sweep: See how density approaches 100% as dimension k increases

Modular Pattern: Observe how residue class distributions change with modulus

Advanced Export Center ?

Export high-resolution images with custom titles, subtitles, and legends. Choose resolution and canvas to export.

Export Settings

6 decimal places

Quick Export Presets

Export preview will appear here

Export Features:

- High-resolution output (up to 8K: 7680×4320)

- Custom titles, subtitles, and legends

- Automatic parameter documentation

- Clean layout without overlap

- Professional formatting for publications

- Timestamp and attribution options

- Configurable decimal precision (2-17 places)

- Full precision data preservation

CSV Export Features:

- Descriptive headers with metadata

- ISO 8601 timestamps

- Full attribution and licensing info

- Up to 17 decimal places for high-k dimensions

- Comment lines (# prefix) for documentation

- Automatic precision selection based on dimension

Farey Sequences & Visible Points ?

The Farey sequence F_n contains all reduced fractions p/q where 0 ≤ p ≤ q ≤ n. These correspond to primitive lattice points and visible points from the origin.

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Fractions in F_n
0
Sum of φ(k)
0%
Density
N/A
Sample Mediant

Farey Sequence Properties:

• F_n = {p/q : 0 ≤ p ≤ q ≤ n, gcd(p,q) = 1}

• |F_n| = 1 + Σ_{k=1}^n φ(k) where φ is Euler's totient

• Mediant property: If p/q and r/s are consecutive in F_n, then (p+r)/(q+s) appears in F_{q+s}

• Connection to continued fractions and best rational approximations

• Ford circles: Circle at p/q with radius 1/(2q²) - consecutive circles are tangent

Save & Load Session ?

Save your current parameters and visualization state to continue your research later or share configurations with others.

Save Current Session

Load Session

Saved Sessions

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What Gets Saved:

• All radius and dimension parameters

• Color modes and visualization settings

• Active tab and display preferences

• Table sizes and configurations

• Label and zoom settings

Note: Sessions are stored in your browser's local storage and persist between visits.

This tab has been removed

Features from the roadmap have been implemented throughout the platform. See the Farey Sequences tab and Save/Load Session tab for newly added functionality.

Interactive Derivation

Step 1: Counting Lattice Points

Start with all lattice points in a k-dimensional sphere of radius R:

$$L_k(R) = |\{(x_1,...,x_k) \in \mathbb{Z}^k : x_1^2 + ... + x_k^2 \leq R^2\}|$$

Asymptotically, this equals the volume: L_k(R) ~ V_k R^k

Step 2: Separating by GCD

Partition points by their greatest common divisor d:

$$L_k(R) = \sum_{d=1}^{R} N_k(R/d)$$

Where N_k(R/d) counts primitive points in a sphere of radius R/d.

Step 3: Möbius Inversion

Inverting the previous relation using Möbius function:

$$N_k(R) = \sum_{d=1}^{R} \mu(d) L_k(R/d)$$

Step 4: Asymptotic Expansion

Substituting L_k(R/d) ~ V_k (R/d)^k:

$$N_k(R) = V_k R^k \sum_{d=1}^{\infty} \frac{\mu(d)}{d^k} + O(R^{k-1})$$

Step 5: Zeta Connection

The sum equals the reciprocal of the zeta function:

$$\sum_{d=1}^{\infty} \frac{\mu(d)}{d^k} = \frac{1}{\zeta(k)}$$

Final Result

$$N_k(R) = \frac{V_k R^k}{\zeta(k)} + O(R^{k-1})$$

This elegant formula connects geometry (V_k), analysis (ζ(k)), and number theory (primitive points)!

Interactive Derivation Animation

Watch the derivation unfold step-by-step, showing how Möbius inversion leads to the zeta function connection.

Step 1 of 7: Introduction

Step 1: Count All Lattice Points

We begin by counting all lattice points (x,y) where x² + y² ≤ R². This gives us L_k(R), the total count including both primitive and non-primitive points.

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Total Points L(R)
0
Primitive Points N(R)
1
Current GCD d
0
μ(d) Value
0
Step Contribution

Bibliography & References

Hardy, G. H., & Wright, E. M. (1979). An Introduction to the Theory of Numbers. Oxford University Press.

Classical proofs for 6/π² density and fundamental results in coprimality.

Dirichlet, G. L. (1849). Über die Bestimmung der mittleren Werthe in der Zahlentheorie.

Foundational work on lattice point problems and average values in number theory.

Mertens, F. (1874). Über einige asymptotische Gesetze der Zahlentheorie.

Refinement of error bounds in arithmetic sums and the Mertens function.

Titchmarsh, E. C. (1986). The Theory of the Riemann Zeta-Function. Oxford Science Publications.

Connection between error terms and the Riemann Hypothesis.

Cesàro, E. (1883). Probabilité de certains faits arithmétiques.

Early work on the probability interpretation of 6/π².

Pillai, S. S., & Chowla, S. (1930). On the Error Terms in Some Asymptotic Formulae.

Analysis of k=2 error bounds and refinements.

van der Corput, J. G. (1923). Zahlentheoretische Abschätzungen.

Classical O(R^(2/3)) bound for the Gauss circle problem.

Further Reading:

- Apostol, T. M. (1976). Introduction to Analytic Number Theory. Springer-Verlag.

- Nathanson, M. B. (1996). Additive Number Theory: The Classical Bases. Springer.

- Iwaniec, H., & Kowalski, E. (2004). Analytic Number Theory. American Mathematical Society.