This invention provides the processes to efficiently evaluate a Boolean expression of events used to determine if a Smartphone app is to be invoked. Its basis is to establish, for each app, a minimal inverted tree that terminates with leaves that indicate the Boolean expression evaluation of “True” or “False”, where a “True” value indicates the associated app is to be invoked or a “False” indicates the associated app is not to be invoked. The process for minimizing the inverted tree is part of this invention. A metric to measure the efficacy of any inverted tree is also included.