Kelvin function

Etymology
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Noun

 * 1)  Any of class of special functions, usually denoted as two pairs of functions bern(x), bein(x), kern(x) and kein(x) with variable x and given order number n. The former two functions bern(x) and bein(x) respectively correspond to the real part and the imaginary part of the Kelvin differential equation's solution that can be expressed with the Bessel function of the first kind Jn(x), and the latter kern(x) and kein(x) correspond to those that can be expressed with the modified Bessel function of the second kind Kn(x).