What heuristic function or algorithm can be considered as invalid

Question

I have studied several heuristic functions that are valid for solving the classic problem with 8 puzzles, and I know that you can multiply the factor by a valid function to make it invalid, however I am wondering if there is any other invalid heuristic function for the problem with 8 puzzles?

Answer 1

There are all kinds of invalid heuristics in this riddle. Invalid heuristics simply have to overestimate the number of steps that will be required to solve this problem, and therefore one simple invalid heuristic will be

h(S) = infinity

, , , .

, , , . .: -)

Answer 2

.

.

Answer 3

, , , , , .

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