p. 1 — Introduction

Zhang Yurui

张 语 芮

Definition 1.1

identity := "mathemati"

∀ challenges ∈ ℝ, ∃ solution ∈ mind

A high school student who quit competition math, rediscovered it through real analysis, and found that the perfect fifth is a continued fraction convergent.

§ 1 — About

A mind that finds order in chaos

I'm a high school student at Chongqing Weiming School, applying to U.S. universities in the Class of 2026. I transferred here this semester, seeking an environment that could support the mathematical depth I was hungry for — my previous school offered AP courses but not the kind of mentorship I needed for serious mathematical study.

My mathematical journey began with competition training in middle school, hit a wall of burnout, and was quietly rekindled by the elegance of AMC/AIME problems. Now I'm working through real analysis — ε-δ definitions, uniform convergence, Fourier series — and finding that abstraction isn't obscurantism. It's clarity.

Outside of math, I hold a Level 8 National Art Certificate in sketch drawing, and I'm fascinated by how mathematical structures appear in music, architecture, and the natural world.

// quick facts

School
Chongqing Weiming School
transferred this semester
Year
Class of 2026
Focus
Mathematics
real analysis, number theory
Art
Level 8 National Certificate
sketch & fine art

§ 2 — Proof of a mathematician

Six years, one proof

"Six years ago I thought math was a race. Now I know it's a field."

Grade 6

The First Spark

— the good years

Selected for the school math competition team. Trained for Gaolian, learned to love the camaraderie of problem-solving. Math felt alive.

n! = n × (n−1)!
Grade 7

The Burnout

— I thought I was done

Friends left the team. Training became mechanical — endless drills, no joy. A teacher's warning that 'one CMO result determines your fate' extinguished the flame. I quit.

Grades 8–9

A Different Kind of Math

— the turning point

Discovered AMC/AIME. Their emphasis on flexible thinking over computational speed felt like breathing fresh air. A quiet realization: math competition can look different.

AMC → AIME → ?
Grade 10

Real Analysis

— 2 weeks on one theorem

Started working with a Yau competition coach. Built the framework from scratch: ε-δ limits, uniform convergence, parametric integrals, Fourier series. Spent two weeks stuck on proving the equivalence of six completeness theorems — then broke through.

∀ε>0, ∃δ>0: |x−c|<δ ⟹ |f(x)−L|<ε
Grade 10–11

Abstract Algebra

— structure > calculation

Self-studied linear algebra and abstract algebra. Moved from computation to structure — groups, rings, fields, Sylow theorems. The shift from 'how to calculate' to 'why this structure exists' changed everything.

G/N ≅ H
Now

The Open Field

— math is everywhere

Exploring number theory through Diophantine approximation and continued fractions. Discovered their connection to musical tuning systems — why the perfect fifth sounds harmonious is a question about rational approximations of log₂(3).

φ = [1; 1, 1, 1, ...] = (1+√5)/2

"Mathematics is not a racetrack with a finish line. It is an open field — and curiosity is the only fuel that doesn't run out."

— from my application essay

§ 3 — Academic record

Scores & examinations

AP courses taken at previous school · self-directed study in real analysis & abstract algebra

AP Examinations

AP Calculus BC
2024
5
AP Physics C: Mechanics
2025
5
AP Statistics
2025
4
AP Computer Science A
2025
4
AP CS Principles
2025
4

Honors & competitions

Yau Mathematical Sciences Award
女子丘成桐数学奥赛 (WMSA)
Finalist
2024 · top-tier
Physics Bowl
American Association of Physics Teachers
Super Gold Award
2024 · 超级金奖
AMC 12A / 12B + AIME
American Mathematics Competition
AMC 12A 121.5 · 12B 130.5 · AIME 11
2025 · AIME qualifier
IMMC International
International Mathematical Modeling Challenge
Meritorious (国际一等奖) + Winter Finalist
2024 · top 10%
TFF Policy Hackathon
The Forum Foundation
Global Finalist
2024 · policy writing
National Art Certificate
全国美术等级考试
Level 8 (Highest)
2023 · sketch

§ 4 — Activities & projects

Beyond the proof

Math is the lens. Everything else is what I see through it.

Artthe longest commitment

National Art Certificate — Level 8

Passed the national standardized sketch examination at the highest level. Nine years of drawing practice, from observation to abstraction.

STEMfounding member

Women in STEM Club

Founding member of the school's Women in STEM initiative, creating space for female students to pursue rigorous science and mathematics.

Researchbiology × data

Household Composting Project

Designed and implemented a kitchen waste composting system, studying microbial decomposition rates and soil nutrient recovery.

Designongoing

Plant Model Library & Bio-Illustration

Building a 3D plant model database combining architectural modeling techniques with biological illustration. Bridges design, biology, and computational geometry.

Communityarchitecture × social impact

Age-Friendly Design Project

Community service initiative redesigning public spaces for elderly accessibility. Applying landscape architecture principles to real-world social challenges.

Art24 pieces

24 Solar Terms Calendar

Creating an illustrated calendar combining traditional Chinese ink painting and oil painting techniques, one artwork per solar term.

§ 5 — Explorations

Where math meets the world

// a question that started everything

Why does the perfect fifth sound harmonious?

My interest in number theory grew from Diophantine approximation: how well can we approximate irrational numbers with rationals? Continued fractions are the optimal tool.

Musical harmony is the same question. The octave is a 2:1 frequency ratio. The perfect fifth is 3:2. Consonant intervals correspond to simple integer ratios — the foundation of just intonation.

Equal temperament? It's the rational approximation of 2^(1/12) — making all intervals slightly impure so all keys are equally usable. The twelve-tone system is a continued fraction convergent.

2 : 1
Octave2^(12/12) = 2.000
3 : 2
Perfect Fifth2^(7/12) ≈ 1.498
4 : 3
Perfect Fourth2^(5/12) ≈ 1.335
5 : 4
Major Third2^(4/12) ≈ 1.260
9 : 8
Major Second2^(2/12) ≈ 1.122

consonance ≈ simplicity of ratio ≈ quality of approximation

Architecture & Landscape

Fascinated by how mathematical structures — tessellations, minimal surfaces, fractal geometries — manifest in built and natural environments.

future study direction

Sketch & Fine Art

Nine years of drawing practice. Level 8 National Certificate. Art as a different language for describing structure and form.

Level 8 certified

Interdisciplinary Thinking

The most interesting questions live at the borders: math × music, biology × geometry, architecture × topology.

the real subject

§ 6 — Contact

Let's talk about mathematics

Whether it's a hard problem, a beautiful proof, or a question about continued fractions and musical tuning — I'm always up for a conversation.

Chongqing Weiming School
Class of 2026 · Mathematics & Architecture
φ = [1; 1, 1, 1, ...] = (1+√5)/2