# Pastebin cnvKmkNi
\proto{eqv?}{ \vari{obj} \varii{obj}}{procedure}}

The {\cf eqv?} procedure defines a useful equivalence relation on objects.
Briefly, it returns \schtrue{} if \vari{obj} and \varii{obj} are
normally regarded as the same object.  This relation is left slightly
open to interpretation, but the following partial specification of
{\cf eqv?} holds for all implementations of Scheme.

The {\cf eqv?} procedure returns \schtrue{} if:

\begin{itemize}
\item \vari{obj} and \varii{obj} are both \schtrue{} or both \schfalse.

\item \vari{obj} and \varii{obj} are both symbols and are the same
symbol according to the {\cf symbol=?} procedure
(section~\ref{symbolsection}).

\item \vari{obj} and \varii{obj} are both exact numbers and
are numerically equal (in the sense of {\cf =}).

\item \vari{obj} and \varii{obj} are both inexact numbers such that
they are numerically equal (in the sense of {\cf =})
and they yield the same results (in the sense of {\cf eqv?})
when passed as arguments to any other procedure
that can be defined as a finite composition of Scheme's standard
arithmetic procedures, provided it does not result in a NaN value.

\item \vari{obj} and \varii{obj} are both characters and are the same
character according to the {\cf char=?} procedure
(section~\ref{charactersection}).

\item \vari{obj} and \varii{obj} are both the empty list.

\item \vari{obj} and \varii{obj} are pairs, vectors, bytevectors, records,
or strings that denote the same location in the store
(section~\ref{storagemodel}).

\item \vari{obj} and \varii{obj} are procedures whose location tags are
equal (section~\ref{lambda}).
\end{itemize}

The {\cf eqv?} procedure returns \schfalse{} if:

\begin{itemize}
\item \vari{obj} and \varii{obj} are of different types
(section~\ref{disjointness}).

\item one of \vari{obj} and \varii{obj} is \schtrue{} but the other is
\schfalse{}.

\item \vari{obj} and \varii{obj} are symbols but are not the same
symbol according to the {\cf symbol=?} procedure
(section~\ref{symbolsection}).

\item one of \vari{obj} and \varii{obj} is an exact number but the other
is an inexact number.

\item \vari{obj} and \varii{obj} are both exact numbers and
are numerically unequal (in the sense of {\cf =}).

\item \vari{obj} and \varii{obj} are both inexact numbers such that either
they are numerically unequal (in the sense of {\cf =}),
or they do not yield the same results (in the sense of {\cf eqv?})
when passed as arguments to any other procedure
that can be defined as a finite composition of Scheme's standard
arithmetic procedures, provided it does not result in a NaN value.
As an exception, the behavior of {\cf eqv?} is unspecified
when both \vari{obj} and \varii{obj} are NaN.

\item \vari{obj} and \varii{obj} are characters for which the {\cf char=?}
procedure returns \schfalse{}.

\item one of \vari{obj} and \varii{obj} is the empty list but the other
is not.

\item \vari{obj} and \varii{obj} are pairs, vectors, bytevectors, records,
or strings that denote distinct locations.

\item \vari{obj} and \varii{obj} are procedures that would behave differently
(return different values or have different side effects) for some arguments.

\end{itemize}