aⁿ + bⁿ ≠ cⁿn > 2
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Fermat's Last Theorem

1637 CE17th-century France (Fermat)

Concept

No integer solutions for x^n + y^n = z^n when n>2 — Fermat's 1637 margin note, finally proved by Wiles in 1994.

Understand it in one breath

"x² + y² = z² has infinitely many integer solutions, but for n ≥ 3 there are none." Fermat's marginal note became public in a posthumous 1670 edition. Wiles worked privately from 1986, announced a result in 1993, and repaired a gap with Richard Taylor in 1994. The two papers appeared in the 1995 Annals of Mathematics.

At a glance

Year

Person

Advance

1637

Fermat

Conjectured in a book margin (a copy of Diophantus)

1770

Euler

Proof for n = 3 (though a gap was later found)

1825

Dirichlet and Legendre

n = 5

1839

Lamé

n = 7 (using Germain’s theorem)

1908

Wolfskehl Prize

100,000-mark prize — inspired countless false proofs

1955

Taniyama–Shimura conjecture

Conjectured that every elliptic curve is modular

1982

Frey

Proposed that an FLT counterexample ⇒ a non-modular elliptic curve

1986

Ribet

Proved the epsilon conjecture → completed the bridge between FLT and Taniyama–Shimura

1993 announcement / 1994 repair / 1995 publication

Andrew Wiles (+ Richard Taylor)

Two papers completed the argument after years of concentrated private work

The simplest-looking statement took 358 years to solve — and the solution came from entirely different fields: elliptic curves and modular forms.

Key formula

xn+yn=zn,    n>2    no positive integer solutionx^n + y^n = z^n,\;\; n > 2 \;\Longrightarrow\; \text{no positive integer solution}

Worked examples

  1. 1

    Q.n=2: 3² + 4² = ?

  2. 2

    Q.n=3: are there positive integer solutions to x³ + y³ = z³?

Key moments

1637 CE

A note in the margin

Fermat wrote in the margin of his copy of Diophantus: “I have discovered a truly marvelous proof, which this margin is too narrow to contain.”

1770 CE

Euler proves the case n=3

Euler used infinite descent to establish the n=3 case, but even he could not reach a general proof.

1908 CE

The 100,000-mark Wolfskehl Prize

Paul Wolfskehl endowed a 100,000-mark prize for a proof, drawing generations of professional and amateur attempts.

1994 CE

Wiles — the end of 357 years

After seven years of secret work and another year repairing a critical gap, Andrew Wiles completed the proof — 357 years after Fermat’s marginal note.

Modern applications

A driving force behind algebraic geometry, Galois representations, modular forms, and the broader toolkit of modern number theory. The mathematics built for the proof is an even larger legacy than the theorem itself.

Beyond MathVoyage

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