--- a/model/ProvenanceModel.html Thu Jul 21 10:13:32 2011 +0100
+++ b/model/ProvenanceModel.html Thu Jul 21 12:00:17 2011 +0100
@@ -339,13 +339,9 @@
<p>A BOB assertion
is about a characterized entity, whose situation in the world is variant.
A BOB assertion is made at a particular point and is invariant, in the sense that
-some of the attributes are assigned a value as part of that assertion.
+all the attributes are assigned a value as part of that assertion.
</p>
-<div class="note"> "some of the attributes are assigned ..." ... I would say "attributes are assigned"
-</div>
-
-
<p>A BOB assertion, noted <b>bob(id, [ attr: val, ...])</b>:
<ul>
<li> contains an identifier <b>id</b>;</li>
@@ -570,11 +566,9 @@
<p><dfn id="dfn-IVPof">IVP of</dfn> is a relationship between two characterized entities asserted to have compatible characterization over some continuous time interval. Compatibility is based upon a partial mapping amongst attributes used in the BOBs used to represent the characterization (the identity mapping is a special case whereby the Bobs share some of the attributes).
-Establishing such relationship would in theory require knowledge of both characterizations. In practice, it is designed in such a way so that one entity communicates its properties and values, whereas the other receives communicated values, and compares with its own values. Hence, it is designed to be an asymmetric relation.</p>
+The "IVP of" relationship is designed to represent pairs of BOBs that correspond to each other. By their own nature, a BOB remains valid only as long as all of its attributes do not change their value. It follows that the correspondence "B IVP of A" is only valid within the time interval during which such invariance property holds for both A and B. When any of the property values change in either A or B, those BOBs are replaced by new ones, and a new correspondence may be established. Thus, "IVP of" is defined relative to the intersection of the temporal intervals for which A and B are valid.
+</p>
-<div =class='note'>I would rephrase the second part as follows:<br/>
-The "IVP of" relationship is designed to represent pairs of BOBs that correspond to each other. By their own nature, a BOB remains valid only as long as all of its attributes do not change their value. It follows that the correspondence "B IVP of A" is only valid within the time interval during which such invariance property holds for both A and B. When any of the property values change in either A or B, those BOBs are replaced by new ones, and a new correspondence may be established. Thus, "IVP of" is defined relative to the intersection of the temporal intervals for which A and B are valid.
-</div>
<p>An IVP assertion is denoted <b>IVPof(B,A)</b>, where A and B are two BOBs.
@@ -603,7 +597,7 @@
<p>
An assertion "B is an IVP of A" holds over the temporal intersection of A and B, <em>only if</em>:
<ol>
- <li>the attributes that A and B share must have equal values. <em>PM: more generally: if a mapping can be established between an attribute X of A and an attribute Y of B, then the values of A and B must be consistent with that mapping</em> </li>
+<li> if a mapping can be established from an attribute X of B to an attribute Y of A, then the values of A and B must be consistent with that mapping</em> </li>
<li>B has some attribute that A does not have
</li></ol>
</p>