Zero-th power of zero

Fixes ethereum#257

Paper.tex

@@ -1578,7 +1578,7 @@ \subsection{Instruction Set}
 \begin{tabular*}{\columnwidth}[h]{rlrrl}
 \toprule
 \multicolumn{5}{c}{\textbf{0s: Stop and Arithmetic Operations}} \\
-\multicolumn{5}{l}{All arithmetic is modulo $2^{256}$ unless otherwise noted.} \vspace{5pt} \\
+\multicolumn{5}{l}{All arithmetic is modulo $2^{256}$ unless otherwise noted. The zero-th power of zero $0^0$ is defined to be one.} \vspace{5pt} \\
 \textbf{Value} & \textbf{Mnemonic} & $\delta$ & $\alpha$ & \textbf{Description} \vspace{5pt} \\
 0x00 & {\small STOP} & 0 & 0 & Halts execution. \\
 \midrule