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...	...	@@ -14,29 +14,30 @@
14	14	Reading tuples can be
15	15	* //destructive// — #code("in"), #code("inp") remove the matching tuple — or //non-destructive// — #code("rd"), #code("rdp") simply read the matching tuple
16	16	* //suspensive// — #code("in"), #code("rd") wait until a matching tuple is found — or //non-suspensive// — #code("inp"), #code("rdp") immediately return either the matching tuple or a failure result
17		-
	17	+<p/>
18	18	but is anyway always //non-deterministic//: when more than one tuple in a tuple centre are found that match a tuple template, one is non-deterministically chosen among them and returned.
19		-
	19	+<p/>
20	20	Accordingly, a tuple centre enjoys all the many features of a tuple space, which can be classified along three different dimensions:
	21	+
21	21	* generative communication
22	22	* associative access
23	23	* suspensive semantics
24		-
	25	+<p/>
25	25	The main features of //generative communication// (where information generated has an independent life with respect to the generator) are the forms of uncoupling (space, time, name) based on mediated interaction: sender and receiver do not need to know each other, to coexist in the same space or at the same time in order to communicate (to exchange a tuple, in particular), and more generally, to interact.
26	26	##
27	27	//Associative access// (access based on structure and content of information exchanged, rather than on location, or on name) based on tuple matching promotes synchronisation based on tuple structure and content: thus, coordination is data-driven, and allows for knowledge-based coordination patterns.
28	28	##
29	29	Finally, //suspensive semantics// promotes coordination patterns based on knowledge availability, and couples well with incomplete, partial knowledge.
30		-
	31	+<p/>
31	31	Even more, while the basic tuple centre model is independent of the type of tuple, #respect() tuple centres adopt logic tuples &mdash; both tuples and tuple templates are essentially Prolog //facts// &mdash; and logic //unification// is used as the tuple-matching mechanism.
32	32	##
33		-So, for instance, an agent #code("ag1") performing operation #code("we ? in(activity(ag1,CaseID))") on tuple centre #code("we") containing tuples #code("activity(ag1,c16)") and #code("activity(ag2,c22)") will be returned tuple #code("activity(ag1,c16)")—the one unifying with the template &mdash; removed from #code("we").
	34	+So, for instance, an agent #code("ag1") performing operation #code("we ? in(activity(ag1,CaseID))") on tuple centre #code("we") containing tuples #code("activity(ag1,c16)") and #code("activity(ag2,c22)") will be returned tuple #code("activity(ag1,c16)") &mdash; the one unifying with the template &mdash; removed from #code("we").
34	34	##
35	35	Since the overall content of a tuple centre is a multiset of logic facts, it has a twofold interpretation as either a collection of messages, or a (logic) //theory of communication// among agents &mdash; thus promoting in principle forms of //reasoning about communication//.
36		-
	37	+<p/>
37	37	Finally, a tuple centre is a programmable tuple space, so as to add //programmability// of the coordination medium as a new dimension of coordination.
38	38	##
39		-While the behaviour of a tuple space in response to interaction events is fixed – so, the effects of coordination primitives is fixed –, the behaviour of a tuple centre can be tailored to the system needs by defining a set of specification tuples, or reactions, which determine how a tuple centre should react to incoming / outgoing events.
	40	+While the behaviour of a tuple space in response to interaction events is fixed &mdash; so, the effects of coordination primitives is fixed &mdash;, the behaviour of a tuple centre can be tailored to the system needs by defining a set of specification tuples, or reactions, which determine how a tuple centre should react to incoming / outgoing events.
40	40	##
41	41	While the basic tuple centre model is not bound to any specific language to define reactions, #respect() tuple centres are obviously programmed through the #respect() logic-based specification language.
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