New result for Mordell’s cube sum problem

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Mordell’s cube sum problem

In 1957, British-American mathematician Louis Mordell asked whether, given some integer $k$, there are integers $x, y, z$ such that $x^3 + y^3 + z^3 = k$. Like Fermat’s last theorem, this problem is very easily stated but very difficult to explore, much less solve definitively.

Some solutions are easy. When $k = 3$, for instance, there are two simple solutions: $1^3 + 1^3 + 1^3 = 3$ and $4^3 + 4^3 + (-5)^3 = 3$. It is also known that there are no solutions in other cases, including

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A Pi Day crossword puzzle

Once again Pi Day (March 14, or 3/14 in North American notation) is here, a day when both professional mathematicians and students alike celebrate this most famous of mathematical numbers.

San Francisco’s Exploratorium is featuring several events, culminating with a “Pi Procession” at 1:59pm Pacific Time (corresponding to 3.14159) and pie served at 2:15pm. The website teachpi.org lists 50 ideas to make Pi Day “entertaining, educational, tasty and fun.”

For this year’s Pi Day festivities, the Math Scholar blog presents a Pi Day crossword puzzle (see below), created by the present author. We will announce the first correct solver! Send

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Simple proofs: Archimedes’ calculation of pi

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Credit: Ancient Origins

Introduction

Archimedes is widely regarded as the greatest mathematician of antiquity. He was a pioneer of applied mathematics, for instance with his discovery of the principle of buoyancy, and a master of engineering designs, for instance with his “screw” to raise water from one level to another. But his most far-reaching discovery was the “method of exhaustion,” which he used to deduce the area of a circle, the surface area and volume of a sphere and the area under a parabola. Indeed, with this method Archimedes anticipated, by nearly

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Simple proofs: The fundamental theorem of calculus

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Isaac Newton, Credit: sjisblog.com

Introduction: The fundamental theorem of calculus, namely the fact that integration is the inverse of differentiation, is indisputably one of the most important results of all mathematics, with applications across the whole of modern science and engineering. It is not an exaggeration to say that our entire modern world hinges on the fundamental theorem of calculus. It has applications in astronomy, astrophysics, quantum theory, relativity, geology, biology, economics, just to name a few fields of science, as well as countless applications in all types of engineering — civil,

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Is scientific progress real?

Top 500 supercomputer performance (orange = #1, blue = #500, green = sum)

Postmodern denials of scientific progress

The fact that scientific research has made immense progress over the past years, decades and centuries is taken for granted among professional scientists and most of the lay public as well. But there are others, from both the left wing and the right wing of society, who question, dismiss or even reject the notion that science progresses. One group, which is mostly rooted in the right wing of society, rejects the scientific consensus on evolution, as with the creationism and intelligent

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2018: The year that artificial intelligence came of age

AI’s tortuous history

The field of artificial intelligence (AI) is actually rather old. Ancient Greek, Chinese and Indian philosophers developed principles of formal reasoning several centuries before Christ. In 1651, British philosopher Thomas Hobbes wrote in Leviathan that “reason … is nothing but reckoning (that is, adding and subtracting).” In 1843 century Ada Lovelace, widely considered to be the first computer programmer, ventured that machines such as Babbage’s analytical engine “might compose elaborate and scientific pieces of music of any degree of complexity or extent.”

In 1950 Alan Turing’s landmark paper Computing machinery and intelligence outlined the principles of AI

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US leads but China rises in latest Top500 supercomputer list

This annual Supercomputing conference is a showcase for the field of high-performance scientific and mathematical computing, featuring a first-rate peer-reviewed technical program, tutorials, workshops, and a massive exhibit hall where universities, national laboratories and computer vendors from around the world exhibit their research, hardware and software. This year’s conference, SC18, which is being held in Dallas, Texas, has attracted well over 10,000 attendees. The conference is co-sponsored by the Association for Computing Machinery (ACM) and the Computer Society of the Institute of Electrical and Electronic Engineers (IEEE).

Awards

Four prestigious professional society awards are presented at the SC18 conference. This

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Simple proofs: The impossibility of trisection

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Credit: Vatican Museum

Introduction: Ancient Greek mathematicians developed the methodology of “ruler-and-compass” constructions: if one is given only a ruler (without marks) and a compass, what objects can be constructed as a result of a finite set of operations? While they achieved many successes, three problems confounded their efforts: (1) squaring the circle; (2) trisecting an angle; and (3) duplicating a cube (i.e., constructing a cube whose volume is twice that of a given cube). Indeed, countless mathematicians through the ages have attempted to solve these problems, and countless incorrect “proofs” have

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Simple proofs: The fundamental theorem of algebra

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Credit: MathIsFun.com

The fundamental theorem of algebra is the assertion that every polynomial with real or complex coefficients has at least one complex root. An immediate extension of this result is that every polynomial of degree $n$ with real or complex coefficients has exactly $n$ complex roots, when counting individually any repeated roots.

This theorem has a long, tortuous history. In 1608, Peter Roth wrote that a polynomial equation of degree $n$ with real coefficients may have $n$ solutions, but offered no proof. Leibniz and Nikolaus Bernoulli both asserted that quartic polynomials of

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Simple proofs: The irrationality of pi

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Credit: fjordstone.com

Mankind has been fascinated with $\pi$, the ratio between the circumference of a circle and its diameter, for at least 2500 years. Ancient Hebrews used the approximation 3 (see 1 Kings 7:23 and 2 Chron. 4:2). Babylonians used the approximation 3 1/8. Archimedes, in the first rigorous analysis of $\pi$, proved that 3 10/71 < $\pi$ < 3 1/7, by means of a sequence of inscribed and circumscribed triangles. Later scholars in India (where decimal arithmetic was first developed, at least by 300 CE), China and the Middle East computed

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