\magnification=1200 \hsize=4in \overfullrule=0pt \input amssym %\def\frac#1 #2 {{#1\over #2}} \def\emph#1{{\it #1}} \def\em{\it} \nopagenumbers \noindent % % {\bf Iwao Sato} % % \medskip \noindent % % {\bf Bartholdi Zeta Functions of Fractal Graphs} % % \vskip 5mm \noindent % % % % Recently, Guido, Isola and Lapidus defined the Ihara zeta function of a fractal graph, and gave a determinant expression of it. We define the Bartholdi zeta function of a fractal graph, and present its determinant expression. \bye .