"It is impossible to argue that software code does not employ mathematical influences, because it does. I think Dijkstra’s explanation that a “programmer applies mathematical techniques” is completely true and accurate. Having said this, the fact that mathematical techniques are employed does not as a matter of fact mean that software is mathematical. Under the US patent laws you cannot receive a patent that covers a mathematical equation or a law of nature. You can certainly use mathematical equations and laws of nature as the building blocks to create something that is new and nonobvious that is patentable. So even if software used mathematical equations there would be no prohibition against the patenting of software under a true and correct reading of the US patent laws."
Source: http://www.ipwatchdog.com/2008/12/15/computer-software-is-not-math/id=1040/
