The set of operations available through the interface is not copyrightable in the United States under "Lotus v. Borland", but it can be protected with a utility patent. The law is unclear as to whether transient copies such as those cached when transmitting digital content, or temporary copies in a computer's RAM are “fixed” for the purposes of copyright law. The Ninth Circuit has held that “A derivative work must be fixed to be protected under the Act, but not to infringe.” In "Apple v. Microsoft", the courts established that a look and feel copyright claim must demonstrate that specific elements of a user interface infringe on another work. A program's particular combination of user interface elements is not copyrightable.