Germain corresponded with other mathematicians of her time such as Gauss and Fourrier, after having familiarized herself with the works of Euler, Newton and Fermat. To be accepted by the scientific community of her time, she had to hide her identity, working under the pseudonym of Antoine Auguste Le Blanc, a former student of the École Polytechnique. Her contributions to the field of mathematics include a theorem that bears her name—Sophie Germain's theorem—which states a sufficient condition for a prime number p such that, if three integers x, y and z are solutions to the equation [latex] x^{p}+ y^{p}[/latex] = [latex]z^{p}[/latex], then at least one of the three numbers x, y and z is divisible by the square of p. This statement can be applied to reduce the number of solutions to Fermat's Last Theorem. It was later discovered that she had come very close to the solution of this famous theorem.