EXCALIBUR Adaptive Constraint-Based Agents in Artificial Environments |
[GENERATION] | [Variables] [Nonextensible Constraints] [Extensible Constraints] [Constraint Extensions] |
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Every possible extension of an extensible constraint can be added in one step. Multiple similar extensions between the same elements can be prohibited by further NACs for the production. These are not vital structural constraints but save from redundancy.
There must be one production for every possible extension of an extensible constraint:
Construction P_{extensiblee}: The right-hand side of the production is an extension graph of E. The left-hand side is created by the vertices of the right-hand side, an NAC for each edge of the right-hand side, and, if p_{max} is not empty, an NAC consisting of the constraint's maximal embedding graph p_{max} such that the constraint is unified with the constraint of the right-hand side (NAC without the constraint itself). In the same way as the last NAC, further NACs have to be introduced for all other constraint vertices of the extension graph to prevent from exceeding the constraints' p_{max} graphs.
Production P_{Machinee} in the figure below shows an example for an extension of the Machine object constraint.
For every extension of a constraint, there must be a production to remove the extension. The requirement req_{min} can be satisfied by providing an additional PAC with the p_{base} graph for each constraint:
Construction P_{extensibler}: The production's left-hand side is similar to the extension graph of E, including a PAC that contains the p_{base} graph, such that the constraint is unified with the constraint of the extension graph (PAC without the constraint itself). In the same way as the PAC, further PACs have to be introduced for all other constraint vertices of the extension graph to prevent from falling below the constraints' p_{base} graphs. The right-hand side is the left-hand side without the PACs and the edges.
Production P_{Machiner} in the figure above shows an example for the reduction of the Machine object constraint.
req_{p} is satisfied, as P_{extensibler} is the reversal of P_{extensiblee} without its NACs, and as the PACs cannot endanger the applicability as the existence of the p_{base} graphs is ensure by req_{min}.
[GENERATION] | [Variables] [Nonextensible Constraints] [Extensible Constraints] [Constraint Extensions] |
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Last update:
May 20, 2001 by Alexander Nareyek