96
Definition4.14. Clause 7 eliminates any range that is overlapped by any move in the set
being considered. Clause 6 defines the content of the destination of a move, m,in terms of
the content of its source, considered in a change set that removes the effects of mand all
lower priority move operations. This recursive check of the range will not contain any data
in the source of a higher priority move (because of clause 7). Clause 7 will not eliminate data
because of being the source of mor the lower priority move operations. One final observa-
tion is that for any data that is the source of several moves, only one will have the highest
priority, and that data will occur onlyat the destination of that move.
Claim 4 is trivial. Note that A’(S ¨ c)is not necessarily unconflicted. In order for that to
be true, there must be no c’ e SwithDest(c’) = Dest(c).
Claim 5 is a consequence of the fact that the only clause of
Definition4.14that actually returns anything other than the null sequence is clause 4.
Clause 4 always returns exactly 1 element of an insertion’s content.
Claim 6 is true because every element of an insertion starts off with an address to its
right and its left, and neither of those addresses is the target of any operation. Adding a
change, insertion, move, or copy, does “remove” an address by making it a destination.
However, even the insertion of a null range will create a new address, immediately bounding
the sequence elements to its left and its right. For longer inserted sequences, the leftmost
new address forms the right boundary of the sequence item to the left, and rightmost new
address forms the left boundary of the sequence item to the right. v
These claims provide the basis for modeling system activities like version management
and undo.
• Claim 1 means that addresses do not vanish when changes are added.
• Claim 2 means that the relative ordering of addresses is preserved when changes are
added to a set.
Definition4.14. Clause 7 eliminates any range that is overlapped by any move in the set
being considered. Clause 6 defines the content of the destination of a move, m,in terms of
the content of its source, considered in a change set that removes the effects of mand all
lower priority move operations. This recursive check of the range will not contain any data
in the source of a higher priority move (because of clause 7). Clause 7 will not eliminate data
because of being the source of mor the lower priority move operations. One final observa-
tion is that for any data that is the source of several moves, only one will have the highest
priority, and that data will occur onlyat the destination of that move.
Claim 4 is trivial. Note that A’(S ¨ c)is not necessarily unconflicted. In order for that to
be true, there must be no c’ e SwithDest(c’) = Dest(c).
Claim 5 is a consequence of the fact that the only clause of
Definition4.14that actually returns anything other than the null sequence is clause 4.
Clause 4 always returns exactly 1 element of an insertion’s content.
Claim 6 is true because every element of an insertion starts off with an address to its
right and its left, and neither of those addresses is the target of any operation. Adding a
change, insertion, move, or copy, does “remove” an address by making it a destination.
However, even the insertion of a null range will create a new address, immediately bounding
the sequence elements to its left and its right. For longer inserted sequences, the leftmost
new address forms the right boundary of the sequence item to the left, and rightmost new
address forms the left boundary of the sequence item to the right. v
These claims provide the basis for modeling system activities like version management
and undo.
• Claim 1 means that addresses do not vanish when changes are added.
• Claim 2 means that the relative ordering of addresses is preserved when changes are
added to a set.
