All posts by Lê Nguyên Hoang

The Surprising Flavor of Infinite Series

July 01, 2013Article11409 vuesEdit
1+2+4+8+16+...=-1, as proven by Henry Reich on Minute Physics! Now, as a mathematician, I must say that his proof is far from being rigorous. In fact, anyone familiar with the surprising flavor of infinite series should not find it convincing. Surprisingly though, his proof can be rigorously and naturally justified! Find out how!

Euler’s Formula and the Utilities Problem

June 20, 2013Article18611 vuesEdit
I was a kid when I was first introduced to the deceptively simple utilities problem. It's only lately that I've discovered its solution! And it's an amazing one! Indeed, it provides a wonderful insight into some fundamental mathematics, including Euler's formula! This is nothing less than the gateway to the wonderful world of algebraic topology!

Proof by Mathematical Induction

June 09, 2013Article6682 vuesEdit
This article explores the potency of proofs by induction with 4 different stunning puzzles, from a lock puzzle and a lion issue, to the monk problem and the pencil conundrum!

Spacetime of General Relativity

June 02, 2013Article14272 vuesEdit
Most popular science explanations of the theory of general relativity are very nice-looking. But they are also deeply misleading. This article presents you a more accurate picture of the spacetime envisioned by Albert Einstein.

Hypothesis Test with Statistics: Get it Right!

May 15, 2013Article4517 vuesEdit
Statistician Johnson recently claimed that up to 25% of published scientific experimental results were just wrong! To see why, let's get to the bottom of the scientific method! And it's probably more complicated than you think. In this article, we apply it rigorously to "prove" $\pi=3$. This will highlight the actually mechanism of the scientific method, its limits, and how much messages of experiments are often deformed!

The Amazing Physics of Water in Trees

April 15, 2013Article65030 vuesEdit
As explained by Derek Muller on Veritasium, the flow of water in trees involves complex physical phenomena including pressure, osmosis, negative pressure, capillarity and evapotranspiration. What seems simple will blow your mind!

A Model of Football Games

April 04, 2013Article7801 vuesEdit
Back then, I simulated the outcome of the 2006 World Cup, based on a modelling of football games. This article explains this model and presents its results.

Poincaré Conjecture and Homotopy

March 25, 2013Article8898 vuesEdit
Poincaré conjecture is the most recent major proven theorem. Posited a century ago by Henri Poincaré, this major conjecture of topology was solved by Gregori Perelman. It has revolutionized our understanding of space and raised intriguing questions regarding the global structure of our Universe.

Shannon’s Information Theory

March 17, 2013Article52398 vuesEdit
Claude Shannon may be considered one of the most influential person of the 20th Century, as he laid out the foundation of the revolutionary information theory. Yet, unfortunately, he is virtually unknown to the public. This article is a tribute to him. And the best way I've found is to explain some of the brilliant ideas he had.

Dynamics of the Wave Function: Heisenberg, Schrödinger, Collapse

March 04, 2013Article10802 vuesEdit
On one hand, the dynamics of the wave function can follow Schrödinger equation and satisfy simple properties like Heisenberg uncertainty principle. But on the other hand, it can be probabilistic. This doesn't mean that it's totally unpredictable, since the unpredictability is amazingly predictable. Find out how these two dynamics work!

Space Deformation and Group Representation

February 22, 2013Article2757 vuesEdit
All along the 20th century, pure algebraists have dug deep into the fundamental structures of mathematics. In this extremely abstract effort, they were greatly help by the possibility of representing these structures by space deformations, which could then be understood much better. This has led to breakthroughs, including the proof of Fermat's las theorem. This article introduces the ideas of group representations.

Conditional Probabilities: Know what you Learn

February 04, 2013Article5017 vuesEdit
Suppose a man has two children, one of them being a boy. What's the probability of the other one being a boy too? This complex question has intrigued thinkers for long until mathematics eventually provided a great framework to better understanding of what's known as conditional probabilities. In this article, we present the ideas through the two-children problem and other fun examples.

The Essence of Quantum Mechanics

January 21, 2013Article11635 vuesEdit
Quantum mechanics is the most accurate and tested scientific theory, Its applications to real life are countless, as all new technologies are based on its principles. Yet, it's also probably the most misunderstood theory, because it constantly contradicts common sense. This article presents the most important features of the theory.

Glaciers: Retreat, Moraines, Valleys, Fjörds

January 09, 2013Article1201 vuesEdit
Glaciers are spectacular phenomenons of nature. The physics they are based on is surprising, while the geological role they have is essential. In this article, we discuss these facts, as well as their retreats and their dangers.

Topology: from the Basics to Connectedness

December 20, 2012Article8281 vuesEdit
Topology was my favorite course in pure maths. I love it because it's a powerful abstract theory to describe intuitive and visual ideas about space. This article gives you an introduction to this amazing field. We'll introduce graph topology, metric spaces, continuity and connectedness.

Construction and Definition of Numbers

December 07, 2012Article9176 vuesEdit
Although they have been used for thousands of years, an actual definition of numbers was given less than a century ago! From the most fundamental level of set theory, this article takes you to the journey of the construction of natural, integer, rational, real and complex numbers.

Self-Reference, Math Foundations and Gödel’s Incompleteness

November 29, 2012Article6632 vuesEdit
Although highly appreciated by artists, self-reference has been a nightmare for mathematicians. It took one of the greatest, Kurt Gödel, to provide a better understanding of it. This article deals with paradoxes, recursion, fractals and Gödel's incompleteness theorems.

The Frontier of Cold: The Quest for Absolute Zero

November 21, 2012Article2478 vuesEdit
While mountaineers aim at tops of mountains, some scientists have sought the bottom of temperature scale with frequent surprising wonders at different scales. This article takes you through these scientists' journey!

Differential Calculus and the Geometry of Derivatives

November 17, 2012Article8052 vuesEdit
Differential calculus is one of the most important concept of mathematics for science and engineering. This article focuses on its fundamental meaning.

Bayesian Games: Math Models for Poker

November 12, 2012Article8184 vuesEdit
How to better understand Poker and card games in general? Bayesian games provide the right mathematical model just for that! These correspond to games with incomplete information and include probabilistic reasonings.