Patentability of computer related inventions in the United States Patent and Trademark Office.

The United State Patent and Trademark Office (PTO) has issued examination guidelines for computer related inventions' applications, beginning in 1995 and prompted by four US Court of Appeals decisions. Previously, the Freeman-Walter-Abele two part test had been used to determine claims containing mathematical subject matter, but the court decisions have moved toward relying on primary authorities. The guidelines have been issued to ensure uniformity and consistency in determining exactly what the applicant has invented and its patentability.