Pi Calculus The l-calculus theory is about modeling systems which have no or little interactions with their environment. On the contrary, the p-calculus theory developed by Robin Milner in the late 1980s is about modeling concurrent communicating systems. This theory also takes into account the notion of "mobility" which can either be physical or, as in the case of B2B, virtual (movement of links between systems). I think we can actually relate the mobility to the notion of "change": change of business partner, business document format, capabilities, etc. Any modification of an existing relationship between two companies may be associated with mobility, such as the dynamic binding with a partner that was not known at design time. 1 References - __Wil van der Aalst, Pi Calculus Versus Petri Nets__. {link:pdf|http://is.tm.tue.nl/research/patterns/download/pi-hype.pdf} 1.1 Related - [BPML] - [XLANG], [BPEL4WS] - [L-Calculus] - [Mobile Calculi] 1.1 Links - http://www.ebpml.org/pi-calculus.htm - http://www.wisdom.weizmann.ac.il/~aviv/pi.htm 2007-03-21 11:31:42.788 2004-10-18 10:26:19.108