Update the PEP to reflect that Exact and Inexact were dropped shortly after Pycon.

pep-3141.txt

@@ -16,10 +16,8 @@ Abstract
 This proposal defines a hierarchy of Abstract Base Classes (ABCs) (PEP
 3119) to represent number-like classes. It proposes a hierarchy of
 ``Number :> Complex :> Real :> Rational :> Integral`` where ``A :> B``
-means "A is a supertype of B", and a pair of ``Exact``/``Inexact``
-classes to capture the difference between ``floats`` and
-``ints``. These types are significantly inspired by Scheme's numeric
-tower [#schemetower]_.
+means "A is a supertype of B". The hierarchy is inspired by Scheme's
+numeric tower [#schemetower]_.
 
 Rationale
 =========
@@ -394,25 +392,6 @@ And finally integers::
             return 1
 
 
-Exact vs. Inexact Classes
--------------------------
-
-Floating point values may not exactly obey several of the properties
-you would expect. For example, it is possible for ``(X + -X) + 3 ==
-3``, but ``X + (-X + 3) == 0``. On the range of values that most
-functions deal with this isn't a problem, but it is something to be
-aware of.
-
-Therefore, we define ``Exact`` and ``Inexact`` ABCs to mark whether
-types have this problem. Every instance of ``Integral`` and
-``Rational`` should be Exact, but ``Reals`` and ``Complexes`` may or
-may not be. (Do we really only need one of these, and the other is
-defined as ``not`` the first?) ::
-
-    class Exact(Number): pass
-    class Inexact(Number): pass
-
-
 Changes to operations and __magic__ methods
 -------------------------------------------