User:Robert Holte/sandbox

A* was created as part of the Shakey project, (cite AI Magazine) which had the aim of building a mobile robot that could plan its own actions. Nils Nilsson originally proposed that the Graph Traverser algorithm (cite GT paper) be used for Shakey's path planning. (cite Quest)   Graph Traverser is guided entirely by the heuristic value of a node, h(n), it ignores g(n). Bertram Raphael suggested using the sum, g(n)+h(n). (cite Quest). Peter Hart invented the concepts we now call admissibility and consistency of heuristics. A* was originally designed for finding least-cost paths when the cost of a path is the sum of its edge costs, but in 2005 it was shown that A* could be used to find optimal paths in any situation satisfying the conditions of a cost algebra (cite cost algebra).

The original 1968 A* paper contained a theorem that no admissible, ``equally informed" algorithm could expand fewer nodes than A* if the heuristic is consistent and A*’s tie-breaking rule is chosen in a rather contrived way. A "correction" was published a few years later (cite correction) claiming that consistency was not required, just admissibility, but this was shown to be false in Dechter and Pearl’s definitive study of A*'s optimal efficiency (cite AAAI paper and JACM paper).

authors like D&P Testing out automatic citation for the Shakey article in the AI Magazine  Here is the automatically generated DP citation  How about links to wikipedia article on the Shakey project and SRI International. Do they have anything on Graph Traverser? No, need a citation. Original A* paper