 In the unusual event that an admissible heuristic is not consistent, a node will need repeated expansion every time a new best (so-far) cost is achieved for it.If the given heuristic formula_14 is admissible but not consistent, one can artificially force the heuristic values along a path to be monotonically non-decreasing
by using 
as the heuristic value for formula_17 instead of formula_18, where formula_19 is the node immediately preceding formula_17 on the path and formula_21.This idea is due to László Mérō
and is now known as pathmax.