Paul Nahin’s scientific contributions

... In a nutshell, operational calculus is a method by which we treat operators algebraically and give meaning to functions of operators. Although its origin dates back to the foundations of calculus with Gottfried Wilhelm Leibniz, the approach was primarily developed during the 19 th century by British and Irish mathematicians such as Sylvester, Boole, Glaisher, Crofton, and Blizard [7,9], and only fully refined by Oliver Heaviside in the 1890s [17]. A well-known example of this approach is the operator we will employ in this paper, which, as suggested by the form of the integral in Eq. (1), is the shift operator [14] and given in one dimension by the exponential of the derivative operatorD x : ...

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Operational Methods Applied to the Spherical Mean and X-Ray Transform