Duncan Farquharson Gregory

There are a number of theorems in ordinary algebra, which, though apparently proved to be true only for symbols representing numbers, admit of a much more extended application. Such theorems depend only on the laws of combination to which …

to furnish to the student examples by which to illustrate the processes of the Differential and Integral Calculus.

Symbolical algebra is … the science which treats of the combination of operations defined not by their nature, … but by the laws of combination to which they are subject....[W]e suppose the existence of classes of unknown operations subject …