Bruce makes an interesting comment on business rules too: that “routing logic in process gateways” are not “business rules”. That doesn’t really make sense: for sure some gateways will be process-housekeeping decisions of little interest to the business user, but others will surely embed business-critical decisions. On the other hand, it has long been acknowledged that a best practice for BPM is to delegate such business decisions to a managed decision service - hence the explicit new business rule (aka decision) task in BPMN 2.0. And,in the CEP world, for tools like TIBCO BusinessEvents to invoke a decision managed by its Decision Manager tool.
Function answers the question --- what is being done?Technique answers the question -- how something being done?
Application answers the question --- what is the problem being solved?
ExamplesBusiness Activity Monitoring (BAM) is an application type, it solves the problem of controlling the business activities in order to optimize the business, deal with exceptions etc...Business Rules are type of technique --- which can be used to infer facts from other facts or rules (inference rules) , or to determine action when event occurs and condition is satisfied (ECA rules) and more (there are at least half a dozen types of rules, which are techniques to do something).Event Processing is really a set of functions which does what the name indicates -- process events --- processing can be filtering, transforming, enriching, routing, detect patterns, deriving and some more.