The Supreme Court will begin hearing oral arguments in i4i v. Microsoft case today.  i4i, a small Canadian software company, sued Microsoft in 2007 alleging infringement of Word products that can process custom XML.  A jury awarded $290M to i4i and ordered a permanent injunction barring Microsoft from continued sale of infringing products.  The decision was later upheld by the Federal Circuit.  Microsoft filed a petition for Supreme Court review of the decision and argued that the Federal Circuit erred in applying the “clear and convincing” standard of proof required to invalidate a patent. Microsoft claimed i4i’s patent was invalid because of the on sale bar and tried to prove that i4i had offered the product for sale more than a year before filing the patent.  Microsoft is seeking to have the standard of proof for invalidity lowered to “preponderance of the evidence” when the cited art was not previously considered by the PTO.