Mathematics are reasoned to be "a law of nature," and "abstract ideas," and so they are explicitly excluded as unpatentable subject matter under 35 USC 101.
Algorithms are established to be mathematics under Case Law, particularly Chakrabarty, 447 U.S. at 309, 206 USPQ at 197; and Flook, 437 U.S. at 585, 198 USPQ at 195.
Diehr, 450 U.S. at 188-178; establishes that if the patent is for a particular application of an abstract idea, but not for the abstract idea itself, it may be patentable.
>Diehr, 450 U.S. at 188-178; establishes that if the patent is for a particular application of an abstract idea, but not for the abstract idea itself, it may be patentable.
Worth pointing out is that the patent in Diehr claimed a method for curing rubber and contemplated a collection of specialized hardware. Not exactly pure software.
Do you know of any case other than Diehr where the Supreme Court has actually sanctioned a software patent?
Not personally, no. Other than Diehr and Flook, SCOTUS hasn't really dealt with software patents much at all. One of the dissenting justices in Bilski lamented the fact that they didn't deal with the wider issue of system and process patents, particularly as they applied to software.
> Diehr, 450 U.S. at 188-178; establishes that if the patent is for a particular application of an abstract idea, but not for the abstract idea itself, it may be patentable.
So what does that mean, "a^2 + b^2 = c^2" cannot be patented, but "using 'a^2 + b^2 = c^2' to find the length^2 of the hypotenuse of a right triangle" in theory could be (were it "invented" today of course)?
Actually, I should clarify a little: The more recent In re Bilski establishes that a rote process (like finding the length of the hypotenuse in your example) is not patentable. It requires a machine or a tangible transformation. That is, a machine that does this calculation.
Algorithms are established to be mathematics under Case Law, particularly Chakrabarty, 447 U.S. at 309, 206 USPQ at 197; and Flook, 437 U.S. at 585, 198 USPQ at 195.
Diehr, 450 U.S. at 188-178; establishes that if the patent is for a particular application of an abstract idea, but not for the abstract idea itself, it may be patentable.