In mathematics, the Dixon elliptic functions sm and cm are two elliptic functions (doubly periodic meromorphic functions on the complex plane) that map from each regular hexagon in a hexagonal tiling to the whole complex plane. Because these functions satisfy the identity cm 3 z + sm 3 z = 1 {\displaystyle \operatorname {cm} ^{3}z+\operatorname {sm} ^{3}z=1} , as real functions they parametrize the cubic Fermat curve x 3 + y 3 = 1 {\displaystyle x^{3}+y^{3}=1} , just as the trigonometric functions sine and cosine parametrize the unit circle x 2 + y 2 = 1 {\displaystyle x^{2}+y^{2}=1} .
They were named sm and cm by Alfred Dixon in 1890, by analogy to the trigonometric functions sine and cosine and the Jacobi elliptic functions sn and cn; Göran Dillner described them earlier in 1873.