diff --git a/sledge/dune b/sledge/dune
index 6bf4fcf64..7f06860d1 100644
--- a/sledge/dune
+++ b/sledge/dune
@@ -33,25 +33,14 @@
    ppx_sexp_conv ppx_sexp_value)
  (preprocess no_preprocessing))
 
-(subdir
- src/import
- (library
-  (name import)
-  (public_name sledge.import)
-  (libraries core core_kernel.fheap zarith trace)
-  (flags (:standard))
-  (preprocess
-   (pps ppx_sledge ppx_trace))
-  (inline_tests)))
-
 (subdir
  src
  (library
   (name sledge)
   (public_name sledge)
-  (libraries import)
+  (libraries nonstdlib)
   (flags
-   (:standard -open Import))
+   (:standard -open NS))
   (preprocess
    (pps ppx_sledge ppx_trace))
   (inline_tests)))
@@ -85,9 +74,9 @@
   (package sledge)
   (libraries apron apron.boxMPQ ctypes ctypes.foreign dune-build-info llvm
     llvm.irreader llvm.analysis llvm.scalar_opts llvm.target llvm.ipo
-    llvm.linker shexp.process yojson trace import sledge model)
+    llvm.linker shexp.process yojson trace nonstdlib sledge model)
   (flags
-   (:standard -w -58 -open Import -open Sledge -open Model))
+   (:standard -w -58 -open NS -open Sledge -open Model))
   (preprocess
    (pps ppx_sledge ppx_trace))))
 
diff --git a/sledge/dune-project b/sledge/dune-project
index a0727d625..2ca2950db 100644
--- a/sledge/dune-project
+++ b/sledge/dune-project
@@ -1,5 +1,8 @@
 (lang dune 2.5)
 
+(package
+ (name nonstdlib))
+
 (package
  (name ppx_trace))
 
diff --git a/sledge/src/import/import.ml b/sledge/nonstdlib/NS.ml
similarity index 97%
rename from sledge/src/import/import.ml
rename to sledge/nonstdlib/NS.ml
index 7fb219024..ccb6f2b78 100644
--- a/sledge/src/import/import.ml
+++ b/sledge/nonstdlib/NS.ml
@@ -5,9 +5,9 @@
  * LICENSE file in the root directory of this source tree.
  *)
 
-(** Global namespace opened in each source file by the build system *)
+(** Global namespace intended to be opened in each source file *)
 
-include Import0
+include NS0
 
 (** Failures *)
 
diff --git a/sledge/src/import/import.mli b/sledge/nonstdlib/NS.mli
similarity index 97%
rename from sledge/src/import/import.mli
rename to sledge/nonstdlib/NS.mli
index 312a3f1ab..baec24e6d 100644
--- a/sledge/src/import/import.mli
+++ b/sledge/nonstdlib/NS.mli
@@ -5,9 +5,9 @@
  * LICENSE file in the root directory of this source tree.
  *)
 
-(** Global namespace opened in each source file by the build system *)
+(** Global namespace intended to be opened in each source file *)
 
-include module type of Import0
+include module type of NS0
 
 (** Function combinators *)
 
diff --git a/sledge/src/import/import0.ml b/sledge/nonstdlib/NS0.ml
similarity index 100%
rename from sledge/src/import/import0.ml
rename to sledge/nonstdlib/NS0.ml
diff --git a/sledge/nonstdlib/dune b/sledge/nonstdlib/dune
new file mode 100644
index 000000000..6b8552c03
--- /dev/null
+++ b/sledge/nonstdlib/dune
@@ -0,0 +1,13 @@
+; Copyright (c) Facebook, Inc. and its affiliates.
+;
+; This source code is licensed under the MIT license found in the
+; LICENSE file in the root directory of this source tree.
+
+(library
+ (name NS)
+ (public_name nonstdlib)
+ (libraries core core_kernel.fheap zarith trace)
+ (flags (:standard))
+ (preprocess
+  (pps ppx_sledge ppx_trace))
+ (inline_tests))
diff --git a/sledge/src/import/iArray.ml b/sledge/nonstdlib/iArray.ml
similarity index 99%
rename from sledge/src/import/iArray.ml
rename to sledge/nonstdlib/iArray.ml
index 82346f257..ddb847f70 100644
--- a/sledge/src/import/iArray.ml
+++ b/sledge/nonstdlib/iArray.ml
@@ -7,7 +7,7 @@
 
 (** IArray - Immutable view of an array *)
 
-open Import0
+open NS0
 
 include (
   Array.Permissioned :
diff --git a/sledge/src/import/iArray.mli b/sledge/nonstdlib/iArray.mli
similarity index 99%
rename from sledge/src/import/iArray.mli
rename to sledge/nonstdlib/iArray.mli
index affb41ef5..4ea161cb7 100644
--- a/sledge/src/import/iArray.mli
+++ b/sledge/nonstdlib/iArray.mli
@@ -13,7 +13,7 @@
     structure, it only attempts to make it inconvenient to unintentionally
     mutate. *)
 
-open Import0
+open NS0
 
 include
   module type of Array.Permissioned
diff --git a/sledge/src/import/list.ml b/sledge/nonstdlib/list.ml
similarity index 99%
rename from sledge/src/import/list.ml
rename to sledge/nonstdlib/list.ml
index d5b7b1e34..014a1b594 100644
--- a/sledge/src/import/list.ml
+++ b/sledge/nonstdlib/list.ml
@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  *)
 
-open Import0
+open NS0
 include Core.List
 
 let rec pp ?pre ?suf sep pp_elt fs = function
diff --git a/sledge/src/import/list.mli b/sledge/nonstdlib/list.mli
similarity index 99%
rename from sledge/src/import/list.mli
rename to sledge/nonstdlib/list.mli
index a068ceb02..d5e8eb98d 100644
--- a/sledge/src/import/list.mli
+++ b/sledge/nonstdlib/list.mli
@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  *)
 
-open Import0
+open NS0
 include module type of Core.List
 
 val pp :
diff --git a/sledge/src/import/map.ml b/sledge/nonstdlib/map.ml
similarity index 99%
rename from sledge/src/import/map.ml
rename to sledge/nonstdlib/map.ml
index 7910ff2ad..91791740c 100644
--- a/sledge/src/import/map.ml
+++ b/sledge/nonstdlib/map.ml
@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  *)
 
-open Import0
+open NS0
 include Map_intf
 
 module Make (Key : sig
diff --git a/sledge/src/import/map.mli b/sledge/nonstdlib/map.mli
similarity index 100%
rename from sledge/src/import/map.mli
rename to sledge/nonstdlib/map.mli
diff --git a/sledge/src/import/map_intf.ml b/sledge/nonstdlib/map_intf.ml
similarity index 99%
rename from sledge/src/import/map_intf.ml
rename to sledge/nonstdlib/map_intf.ml
index 6bac231cb..8966cfdb1 100644
--- a/sledge/src/import/map_intf.ml
+++ b/sledge/nonstdlib/map_intf.ml
@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  *)
 
-open Import0
+open NS0
 
 module type S = sig
   type key
diff --git a/sledge/src/import/option.ml b/sledge/nonstdlib/option.ml
similarity index 97%
rename from sledge/src/import/option.ml
rename to sledge/nonstdlib/option.ml
index 4aeb58bc9..6f94a4844 100644
--- a/sledge/src/import/option.ml
+++ b/sledge/nonstdlib/option.ml
@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  *)
 
-open! Import0
+open! NS0
 include Core.Option
 
 let pp fmt pp_elt fs = function
diff --git a/sledge/src/import/option.mli b/sledge/nonstdlib/option.mli
similarity index 97%
rename from sledge/src/import/option.mli
rename to sledge/nonstdlib/option.mli
index 370bebba0..e7e54beea 100644
--- a/sledge/src/import/option.mli
+++ b/sledge/nonstdlib/option.mli
@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  *)
 
-open! Import0
+open! NS0
 include module type of Core.Option
 
 val pp : ('a_pp -> 'a -> unit, unit) fmt -> 'a_pp -> 'a option pp
diff --git a/sledge/src/import/qset.ml b/sledge/nonstdlib/qset.ml
similarity index 99%
rename from sledge/src/import/qset.ml
rename to sledge/nonstdlib/qset.ml
index dc38469a5..b1ff1f006 100644
--- a/sledge/src/import/qset.ml
+++ b/sledge/nonstdlib/qset.ml
@@ -7,7 +7,7 @@
 
 (** Qset - Set with (signed) rational multiplicity for each element *)
 
-open Import0
+open NS0
 include Qset_intf
 
 module Make (Elt : sig
diff --git a/sledge/src/import/qset.mli b/sledge/nonstdlib/qset.mli
similarity index 100%
rename from sledge/src/import/qset.mli
rename to sledge/nonstdlib/qset.mli
diff --git a/sledge/src/import/qset_intf.ml b/sledge/nonstdlib/qset_intf.ml
similarity index 99%
rename from sledge/src/import/qset_intf.ml
rename to sledge/nonstdlib/qset_intf.ml
index 5446290f9..8db51e830 100644
--- a/sledge/src/import/qset_intf.ml
+++ b/sledge/nonstdlib/qset_intf.ml
@@ -7,7 +7,7 @@
 
 (** Qset - Set with (signed) rational multiplicity for each element *)
 
-open Import0
+open NS0
 
 module type S = sig
   type elt
diff --git a/sledge/src/import/set.ml b/sledge/nonstdlib/set.ml
similarity index 99%
rename from sledge/src/import/set.ml
rename to sledge/nonstdlib/set.ml
index ce224bb57..f2a0e0c2e 100644
--- a/sledge/src/import/set.ml
+++ b/sledge/nonstdlib/set.ml
@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  *)
 
-open Import0
+open NS0
 include Set_intf
 
 module Make (Elt : sig
diff --git a/sledge/src/import/set.mli b/sledge/nonstdlib/set.mli
similarity index 100%
rename from sledge/src/import/set.mli
rename to sledge/nonstdlib/set.mli
diff --git a/sledge/src/import/set_intf.ml b/sledge/nonstdlib/set_intf.ml
similarity index 98%
rename from sledge/src/import/set_intf.ml
rename to sledge/nonstdlib/set_intf.ml
index 91f02c5ef..0bdca1ed1 100644
--- a/sledge/src/import/set_intf.ml
+++ b/sledge/nonstdlib/set_intf.ml
@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  *)
 
-open Import0
+open NS0
 
 module type S = sig
   type elt
diff --git a/sledge/src/term.ml b/sledge/src/term.ml
index 5f351f5f8..0599636cf 100644
--- a/sledge/src/term.ml
+++ b/sledge/src/term.ml
@@ -38,13 +38,13 @@ type op3 = Conditional | Extract [@@deriving compare, equal, hash, sexp]
 type opN = Concat | Record [@@deriving compare, equal, hash, sexp]
 
 module rec Set : sig
-  include Import.Set.S with type elt := T.t
+  include NS.Set.S with type elt := T.t
 
   val hash : t -> int
   val hash_fold_t : t Hash.folder
   val t_of_sexp : Sexp.t -> t
 end = struct
-  include Import.Set.Make (T)
+  include NS.Set.Make (T)
 
   let hash_fold_t = hash_fold_t T.hash_fold_t
   let hash = Hash.of_fold hash_fold_t
@@ -53,13 +53,13 @@ end = struct
 end
 
 and Qset : sig
-  include Import.Qset.S with type elt := T.t
+  include NS.Qset.S with type elt := T.t
 
   val hash : t -> int
   val hash_fold_t : t Hash.folder
   val t_of_sexp : Sexp.t -> t
 end = struct
-  include Import.Qset.Make (T)
+  include NS.Qset.Make (T)
 
   let hash_fold_t = hash_fold_t T.hash_fold_t
   let hash = Hash.of_fold hash_fold_t
diff --git a/sledge/src/term.mli b/sledge/src/term.mli
index 59d6ac5d1..026e6fcd7 100644
--- a/sledge/src/term.mli
+++ b/sledge/src/term.mli
@@ -58,14 +58,14 @@ type opN =
 [@@deriving compare, equal, hash, sexp]
 
 module rec Set : sig
-  include Import.Set.S with type elt := T.t
+  include NS.Set.S with type elt := T.t
 
   val hash_fold_t : t Hash.folder
   val t_of_sexp : Sexp.t -> t
 end
 
 and Qset : sig
-  include Import.Qset.S with type elt := T.t
+  include NS.Qset.S with type elt := T.t
 
   val hash_fold_t : t Hash.folder
   val t_of_sexp : Sexp.t -> t
@@ -110,7 +110,7 @@ module Var : sig
   module Map : Map.S with type key := t
 
   module Set : sig
-    include Import.Set.S with type elt := t
+    include NS.Set.S with type elt := t
 
     val hash_fold_t : t Hash.folder
     val sexp_of_t : t -> Sexp.t