First to file and first to invent
（重定向自First to invent system）
First to file (FTF) and first to invent (FTI) are legal concepts that define who has the right to the grant of a patent for an invention. The first-to-file system is used in all countries, including the United States, which switched to a first-inventor-to-file (FITF) system on March 16, 2013 after the enactment of the America Invents Act.