Some minor updates

Paper.tex

@@ -1029,9 +1029,9 @@ \subsection{Basics}
 
 \subsection{Fees Overview}
 
-Fees (denominated in gas) are charged under three distinct circumstances, all three as prerequisite to the execution of an operation. The first and most common is the fee intrinsic to the computation of the operation (see Appendix \ref{app:fees}). Secondly, gas may be deducted in order to form the payment for a subordinate message call or contract creation; this forms part of the payment for {\small CREATE}, {\small CREATE2}, {\small CALL} and {\small CALLCODE}. Finally, gas may be paid due to an increase in the usage of the memory.
+Fees (denominated in gas) are charged under three distinct circumstances, all three as prerequisite to the execution of an operation. The first and most common is the fee intrinsic to the computation of the operation (see Appendix \ref{app:fees}). Secondly, gas may be deducted in order to form the payment for a subordinate message call or contract creation; this forms part of the payment for {\small CREATE}, {\small CREATE2}, {\small CALL}, {\small CALLCODE}, {\small DELEGATECALL}, and {\small STATICCALL}. Finally, gas may be paid due to an increase in the usage of the memory.
 
-Over an account's execution, the total fee for memory-usage payable is proportional to smallest multiple of 32 bytes that are required such that all memory indices (whether for read or write) are included in the range. This is paid for on a just-in-time basis; as such, referencing an area of memory at least 32 bytes greater than any previously indexed memory will certainly result in an additional memory usage fee. Due to this fee it is highly unlikely addresses will ever go above 32-bit bounds. That said, implementations must be able to manage this eventuality.
+Over an account's execution, the total fee for memory-usage payable is specified in \ref{app:vm}. If you use a small amount of memory, this fee is proportional to smallest multiple of 32 bytes that are required such that all memory indices (whether for read or write) are included in the range. For larger amounts of memory the fee is approximately the square of that number. See Appendix \label{app:vm} for the exact expression. This is paid for on a just-in-time basis; as such, referencing an area of memory at least 32 bytes greater than any previously indexed memory will result in an additional memory usage fee. Due to this fee it is highly unlikely addresses will ever go above 32-bit bounds. That said, implementations must be able to manage this eventuality.
 
 Storage fees have a slightly nuanced behaviour---to incentivise minimisation of the use of storage (which corresponds directly to a larger state database on all nodes), the execution fee for an operation that clears an entry in the storage is not only waived, a qualified refund is given; in fact, this refund is effectively paid up-front since the initial usage of a storage location costs substantially more than normal usage.
 
@@ -1076,7 +1076,7 @@ \subsection{Execution Overview}
 \boldsymbol{\mu}_{\mathbf{m}} & \equiv & (0, 0, ...) \\
 \boldsymbol{\mu}_{\mathrm{i}} & \equiv & 0 \\
 \boldsymbol{\mu}_{\mathbf{s}} & \equiv & () \\
-\boldsymbol{\mu}_{\mathbf{o}} & \equiv & ()
+\boldsymbol{\mu}_{\mathbf{o}} & \equiv & $\varnothing$ \\
 \end{eqnarray}
 \begin{equation} \label{eq:X-def}
 X\big( (\boldsymbol{\sigma}, \boldsymbol{\mu}, A, I) \big) \equiv \begin{cases}