Lamé's special quartic, named after Gabriel Lamé, is the graph of the equation
x 4 + y 4 = r 4 {\displaystyle x^{4}+y^{4}=r^{4}}
where r > 0 {\displaystyle r>0} . It looks like a rounded square with "sides" of length 2 r {\displaystyle 2r} and centered on the origin. This curve is a squircle centered on the origin, and it is a special case of a superellipse. Because of Pierre de Fermat's only surviving proof, that of the n = 4 case of Fermat's Last Theorem, if r is rational there is no non-trivial rational point (x, y) on this curve (that is, no point for which both x and y are non-zero rational numbers).
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