*4.2.2 Indirect infringement*

There are actually two types of indirect infringement.


#### *4.2.3 Willful and literal infringement*

Willful infringement involves the concept of intention. Literal infringement refers to incidents involving the exact copy of a patented item being used, sold, or imported.

#### *4.2.4 Doctrine of equivalents infringement*

If the infringing product performs the same function and yields the same results of the patented product, then it is considered as doctrine of equivalent infringement.

Case law: Graver Tank & Manufacturing Co. v. Linde Air Products Co., (1950) [10]- In this case, the Court explained that the doctrine of equivalents applies if two elements are interchangeable and a person with ordinary skill in the art would have known that the elements were interchangeable at the time of infringement.
