6.034 Artificial Intelligence - Recitations, fall 2004 online slides on search
	Optimality of A* Suppose some suboptimal goal $G_2$ has been generated and is in the open list. Let $n$ be an unexpanded node on a shortest path to an optimal goal $G_1$. $$\begin{eqnarray*} f(G_2) & = & g(G_2)\qquad {\rm since }h(G_2) = 0 \\ & > & g... ...al} \\ &\geq& f(n) \qquad {\rm since }h {\rm is admissible} \end{eqnarray*}$$ Since $f(G_2) > f(n)$, A$^*$ will never select $G_2$ for expansion