diff --git a/basis/regexp/classes/classes.factor b/basis/regexp/classes/classes.factor
index 516b6b4a1d..c7106c9154 100644
--- a/basis/regexp/classes/classes.factor
+++ b/basis/regexp/classes/classes.factor
@@ -1,6 +1,6 @@
 ! Copyright (C) 2008, 2009 Doug Coleman, Daniel Ehrenberg.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: accessors kernel math math.order words
+USING: accessors kernel math math.order words combinators
 ascii unicode.categories combinators.short-circuit sequences ;
 IN: regexp.classes
 
@@ -107,20 +107,47 @@ M: end-of-line class-member? ( obj class -- ? )
     2drop f ;
 
 TUPLE: or-class seq ;
-C: <or-class> or-class
 
 TUPLE: not-class class ;
-C: <not-class> not-class
 
-: <and-class> ( classes -- class )
-    [ <not-class> ] map <or-class> <not-class> ;
+TUPLE: and-class seq ;
 
 TUPLE: primitive-class class ;
 C: <primitive-class> primitive-class
 
+: <and-class> ( seq -- class )
+    t swap remove
+    f over member? [ drop f ] [
+        dup length {
+            { 0 [ drop t ] }
+            { 1 [ first ] }
+            [ drop and-class boa ]
+        } case
+    ] if ;
+
+M: and-class class-member?
+    seq>> [ class-member? ] with all? ;
+
+: <or-class> ( seq -- class )
+    f swap remove
+    t over member? [ drop t ] [
+        dup length {
+            { 0 [ drop f ] }
+            { 1 [ first ] }
+            [ drop or-class boa ]
+        } case
+    ] if ;
+
 M: or-class class-member?
     seq>> [ class-member? ] with any? ;
 
+: <not-class> ( class -- inverse )
+    {
+        { t [ f ] }
+        { f [ t ] }
+        [ not-class boa ]
+    } case ;
+
 M: not-class class-member?
     class>> class-member? not ;
 
diff --git a/basis/regexp/dfa/dfa.factor b/basis/regexp/dfa/dfa.factor
index 9834ca4ca0..8c2e995163 100644
--- a/basis/regexp/dfa/dfa.factor
+++ b/basis/regexp/dfa/dfa.factor
@@ -2,8 +2,7 @@
 ! See http://factorcode.org/license.txt for BSD license.
 USING: accessors arrays assocs combinators fry kernel locals
 math math.order regexp.nfa regexp.transition-tables sequences
-sets sorting vectors sequences.deep math.functions regexp.classes ;
-USING: io prettyprint threads ;
+sets sorting vectors ;
 IN: regexp.dfa
 
 :: (while-changes) ( obj quot: ( obj -- obj' ) comp: ( obj -- key ) old-key -- obj )
@@ -17,34 +16,6 @@ IN: regexp.dfa
 : while-changes ( obj quot pred -- obj' )
     3dup nip call (while-changes) ; inline
 
-TUPLE: parts in out ;
-
-: make-partition ( choices classes -- partition )
-    zip [ first ] partition parts boa ;
-
-: powerset-partition ( classes -- partitions )
-    ! Here is where class algebra will happen, when I implement it
-    [ length [ 2^ ] keep ] keep '[
-        _ [ ] map-bits _ make-partition
-    ] map ;
-
-: partition>class ( parts -- class )
-    [ in>> ] [ out>> ] bi
-    [ <or-class> ] bi@ <not-class> 2array <and-class> ;
-
-: get-transitions ( partition state-transitions -- next-states )
-    [ in>> ] dip '[ at ] gather ;
-
-: disambiguate-overlap ( nfa -- nfa' )  
-    [
-        [
-            [ keys powerset-partition ] keep '[
-                [ partition>class ]
-                [ _ get-transitions ] bi
-            ] H{ } map>assoc
-        ] assoc-map
-    ] change-transitions ;
-
 : find-delta ( states transition nfa -- new-states )
     transitions>> '[ _ swap _ at at ] gather sift ;
 
@@ -85,7 +56,8 @@ TUPLE: parts in out ;
 
 : states ( hashtable -- array )
     [ keys ]
-    [ values [ values concat ] map concat append ] bi ;
+    [ values [ values concat ] map concat ] bi
+    append ;
 
 : set-final-states ( nfa dfa -- )
     [
@@ -100,7 +72,6 @@ TUPLE: parts in out ;
         swap find-start-state >>start-state ;
 
 : construct-dfa ( nfa -- dfa )
-    disambiguate-overlap
     dup initialize-dfa
     dup start-state>> 1vector
     H{ } clone
diff --git a/basis/regexp/disambiguate/disambiguate.factor b/basis/regexp/disambiguate/disambiguate.factor
new file mode 100644
index 0000000000..2e26e43625
--- /dev/null
+++ b/basis/regexp/disambiguate/disambiguate.factor
@@ -0,0 +1,38 @@
+! Copyright (C) 2008, 2009 Doug Coleman, Daniel Ehrenberg.
+! See http://factorcode.org/license.txt for BSD license.
+USING: kernel accessors regexp.classes math.bits assocs sequences
+arrays sets regexp.dfa math fry regexp.minimize ;
+IN: regexp.disambiguate
+
+TUPLE: parts in out ;
+
+: make-partition ( choices classes -- partition )
+    zip [ first ] partition [ values ] bi@ parts boa ;
+
+: powerset-partition ( classes -- partitions )
+    [ length [ 2^ ] keep ] keep '[
+        _ <bits> _ make-partition
+    ] map ;
+
+: partition>class ( parts -- class )
+    [ in>> ] [ out>> ] bi
+    [ <or-class> ] bi@ <not-class> 2array <and-class> ;
+
+: get-transitions ( partition state-transitions -- next-states )
+    [ in>> ] dip '[ _ at ] map prune ;
+
+: disambiguate ( dfa -- nfa )  
+    [
+        [
+            [ keys powerset-partition ] keep '[
+                [ partition>class ]
+                [ _ get-transitions ] bi
+            ] H{ } map>assoc
+            [ drop ] assoc-filter 
+        ] assoc-map
+    ] change-transitions ;
+
+: nfa>dfa ( nfa -- dfa )
+    construct-dfa
+    minimize disambiguate
+    construct-dfa minimize ;
diff --git a/basis/regexp/negation/negation.factor b/basis/regexp/negation/negation.factor
index 6b0e6b519e..f235dc1bf5 100644
--- a/basis/regexp/negation/negation.factor
+++ b/basis/regexp/negation/negation.factor
@@ -1,12 +1,12 @@
 ! Copyright (C) 2009 Daniel Ehrenberg.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: regexp.nfa regexp.dfa regexp.minimize kernel sequences
+USING: regexp.nfa regexp.disambiguate kernel sequences
 assocs regexp.classes hashtables accessors fry vectors
-regexp.ast regexp.transition-tables ;
+regexp.ast regexp.transition-tables regexp.minimize ;
 IN: regexp.negation
 
 : ast>dfa ( parse-tree -- minimal-dfa )
-    construct-nfa construct-dfa minimize ;
+    construct-nfa nfa>dfa ;
 
 CONSTANT: fail-state -1
 
diff --git a/basis/regexp/nfa/nfa.factor b/basis/regexp/nfa/nfa.factor
index 370b354276..eff023c278 100644
--- a/basis/regexp/nfa/nfa.factor
+++ b/basis/regexp/nfa/nfa.factor
@@ -20,7 +20,7 @@ M: with-options remove-lookahead
     [ tree>> remove-lookahead ] [ options>> ] bi <with-options> ;
 
 M: alternation remove-lookahead
-    [ first>> ] [ second>> ] bi [ remove-lookahead ] bi@ ;
+    [ first>> ] [ second>> ] bi [ remove-lookahead ] bi@ alternation boa ;
 
 M: concatenation remove-lookahead ;