ABSTRACT
In the nineteenth century mathematicians developed a “symbolic calculus,” a system of
rules for calculation with the operator of differentiation D := ddt .
The papers of Oliver Heaviside (1850-1925) were instrumental in promoting operational
calculus methods. Heaviside applied his calculus in the solution of differential equations,
especially in the theory of electricity. He had a brilliant feel for operator calculus, but
because he did not consider the conditions for the validity of his calculations his results
were sometimes wrong. Heaviside published his results in some papers about operators
in mathematical physics in 1892-1894 and also in his books Electrical Papers (1892) and
Electromagnetic Theory (1899); see [H.1]–[H.3].
