Beauty of Mathematics

Mathematics, rightly viewed, possesses not only truth, but supreme beauty — a beauty cold and austere, like that of sculpture, without appeal to any part of our weaker nature, without the gorgeous trappings of painting or music, yet sublimely pure, and capable of a stern perfection such as only the greatest art can show. The true spirit of delight, the exaltation, the sense of being more than Man, which is the touchstone of the highest excellence, is to be found in mathematics as surely as poetry-- Bertrand Russel.
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Sunday, 3 November 2013

Fermat's Last Theorem



                                           
                            The holy grail of mathematics.


Background of Fermat’s Last Theorem:


Let us first look at positive Integral Solutions of some basic equations. For example let us take an equation a+b=c.  How many positive Integral Solutions does this equation have? Obviously Infinite. We can see that 2+3= 5 or 5+10= 15 and like that infinite solutions.

The next example is     a2+b2=c2.  How many positive Integral Solutions does this equation have? All Pythagorean triplets like 3-4-5, 5-12-13, 8-15-17, 7-24-25… and their multiples like 6-8-10 etc; all are solutions of this equation. So, this equation too has infinite solutions. This particular equation a2+b2=c2 and its solutions are known to mankind for the past two thousand years.  

Such polynomial equations like a2+b2=c2 in which the solutions must be positive integers are known as Diophantine equations. Their name derives from the 3rd-century Alexandrian mathematician, Diophantus, who developed methods for their solutions. Diophantus's major work is the Arithmetica which was written in the third century and remained the source for such equations for next several centuries.

Claude Bachet, a Mathematician, wrote a translation  of Arithmetica in 1621. Pierre de Fermat, a legal adviser and an amateur Mathematician was deeply involved in solving Diophantine equations and got a copy of this book. 

Pierre de Fermat thought about the next higher level Diophantine equations like:

a3+b3=c3
a4+b4=c4
a5+b5=c5
…………………..
an+bn=cn

He spent several years on the above equations and could not find any integral solutions for the above equations. Finally he was convinced that 

an+bn≠cn

Where a,b, c and n are natural Numbers and n>2.

And the above is what is known as Fermat’s Last Theorem.

Pierre de Fermat wrote many theorems on number Theory which all were proved subsequently except the one as mentioned above. However, around 1637, Fermat wrote his above–mentioned most famous Theorem in the margin of his copy of the Arithmetica next to Diophantus' sum-of-squares problem:

 “It is impossible to separate a cube into two cubes, or a fourth power into two fourth powers, or in general, any power higher than the second, into two like powers. I have discovered a truly marvelous proof of this, which this margin is too narrow to contain”.

The Search for the proof of Fermat’s Last theorem:

Those were the most mysterious words ever written by Pierre de Fermat. Decades and centuries went by but nobody could locate the proof written by him. It was lost for ever. It sort of became a big mathematical challenge to prove the theorem. Mathematicians started considering it as a holy grail of Mathematics. Hundreds of Mathematicians including Euler, Gauss, Newton and their worthy successors worked on the problem but could never prove the theorem in the next three and a half centuries till 1995.Many Mathematicians devoted their lives just on this theorem but could not succeed. No successful proof was published until 1995 despite the efforts of countless mathematicians during the 358 intervening years.

That abnormally long time-span of more than 350 years accentuates the significance of this Conjecture- Fermat’s last theorem. It is hard to conceive of any problem, so simply and clearly stated that could have withstood the test of advancing knowledge for so long. 

Let us consider the progress in physics, chemistry, biology, medicine and engineering that have taken place since the seventeenth century. All the subjects have changed beyond recognition. The Physics became quantum Physics. Medicine metamorphosed into genetics. Modern Chemistry makes the chemistry of 17th century look like alchemy. There is no comparison of the primitive technology of the seventeenth century to today’s space age.  But the Fermat’s last theorem (FLT) could not be conquered till 1995.

Mount Everest could be conquered in two to three decades but the FLT took more than 350 yrs. Fermat’s Last Theorem was the Himalayan peak of number theory. And Fermat was the father of modern number theory.

Prizes Declared on the Proof of Fermat’s last theorem:

In 1816 and in 1850, the French Academy of Sciences offered a prize for a general proof of Fermat's Last Theorem. Another prize was offered in 1883 by the Academy of Brussels.
In 1908, the German industrialist and amateur mathematician Paul Wolfskehl bequeathed 100,000 marks to the Göttingen Academy of Sciences to be offered as a prize for a complete proof of Fermat's Last Theorem.

Finally Andrew Wiles a British Mathematician proves the Theorem in 1995:

Sir Andrew John Wiles, a British mathematician and a Royal Society Research Professor at Oxford University, specializing in number theory ultimately proved the Fermat’s last theorem in 1995 with the help of Computers and latest research in the field of Number Theory.

Wiles came to know about Fermat’s Last Theorem when he was 10 years old. He was Surprised by the fact that the statement of the theorem was so easy that he at the age of 10 could understand it.He aspired to be the first person to prove it. However, he soon realized that his knowledge of mathematics was too inadequate, so he abandoned his childhood dream, until 1986, when he heard that Ribet, a famous Mathematician, had established a link between Fermat's Last Theorem and the Taniyama–Shimura conjecture about elliptical curves and modular functions which are intricately linked to each other.

Based on successive progress of the previous few years of renowned Mathematicians like Gerhard Frey, Jean-Pierre Serre and Ken Ribet; he dedicated all of his research time to this problem in relative secrecy. In 1993, he presented his proof to the public for the first time at a conference in Cambridge. However certain errors were noticed by Mathematicians in the Proof.

Wiles tried to correct the mistakes but found out that the gap he had made was significant. The essential idea bypassing, rather than closing this gap, came to him in September 1994. Together with his former student Richard Taylor, he published a second paper which circumvented the gap and thus completed the proof. Both papers were published in 1995 in a special volume of the Annals of Mathematics.

Finally Andrew Wiles collected the well deserved Wolfskehl prize money, then worth $50,000, on 27 June 1997.

Wiles’ proof is well over 100 pages long, and involves some of the most advanced Mathematics of its time, and so the question does linger, “Is there a ‘simple’ proof of the Theorem as originally claimed by Fermat?”