Patent infringement is an unauthorized act of - for example - making, using, offering for sale, selling, or importing for these purposes a patented product. Where the subject-matter of the patent is a process, infringement involves the act of using, offering for sale, selling or importing for these purposes at least the product obtained by the patented process. In other words, patent infringement is the commission of a prohibited act with respect to a patented invention without permission from the patent holder. Permission may typically be granted in the form of a license. The definition of patent infringement may vary by jurisdiction.