Gottschalk v. Benson
Gottschalk v. Benson, 409 U.S. 63 (1972), was a United States Supreme Court case in which the Court ruled that a process claim directed to a numerical algorithm, as such, was not patentable because "the patent would wholly pre-empt the mathematical formula and in practical effect would be a patent on the algorithm itself." That would be tantamount to allowing a patent on an abstract idea, contrary to precedent dating back to the middle of the 19th century.