Note: This article has been updated to include the name of a law firm involved in one of the cases mentioned.

Intellectual property litigation may be recession-proof. According to a survey by PricewaterhouseCoopers, patent holders brought 2,892 U.S. infringement lawsuits in 2010—an increase of more than 5 percent over the year before. Similarly, the number of reported trade secrets cases increased by 13 percent in 2010, according to research by blogger Russell Beck, a partner at the Boston law firm Beck Reed Riden. Another recession-proof phenomenon is Apple Inc., known lately for must-have mobile gadgets—and now, apparently, for employing legions of IP lawyers in its battle to take down Google Inc.’s Android operating system.