diff --git a/src/library/CMakeLists.txt b/src/library/CMakeLists.txt
index 1b81dc045..2f3318942 100644
--- a/src/library/CMakeLists.txt
+++ b/src/library/CMakeLists.txt
@@ -12,6 +12,6 @@ add_library(library deep_copy.cpp expr_lt.cpp io_state.cpp occurs.cpp
   metavar_closure.cpp reducible.cpp init_module.cpp
   generic_exception.cpp fingerprint.cpp flycheck.cpp hott_kernel.cpp
   local_context.cpp choice_iterator.cpp pp_options.cpp unfold_macros.cpp
-  app_builder.cpp projection.cpp)
+  app_builder.cpp projection.cpp abbreviation.cpp)
 
 target_link_libraries(library ${LEAN_LIBS})
diff --git a/src/library/abbreviation.cpp b/src/library/abbreviation.cpp
new file mode 100644
index 000000000..a408328a8
--- /dev/null
+++ b/src/library/abbreviation.cpp
@@ -0,0 +1,160 @@
+/*
+Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+Released under Apache 2.0 license as described in the file LICENSE.
+
+Author: Leonardo de Moura
+*/
+#include "util/sstream.h"
+#include "kernel/find_fn.h"
+#include "kernel/instantiate.h"
+#include "library/scoped_ext.h"
+#include "library/expr_lt.h"
+#include "library/util.h"
+#include "library/replace_visitor.h"
+
+namespace lean {
+typedef pair<name, bool> abbrev_entry;
+
+struct abbrev_state {
+    name_map<bool>                     m_abbrevs;
+    rb_map<expr, name, expr_quick_cmp> m_inv_map; // for pretty printer
+
+    void add(environment const & env, name const & n, bool parsing_only) {
+        declaration const & d = env.get(n);
+        if (!d.is_definition())
+            throw exception(sstream() << "invalid abbreviation '" << n << "', it is not a definition");
+        m_abbrevs.insert(n, parsing_only);
+        if (!parsing_only)
+            m_inv_map.insert(d.get_value(), n);
+    }
+
+    bool is_abbreviation(name const & n) const { return m_abbrevs.contains(n); }
+
+    bool is_parsing_only_abbreviation(name const & n) const {
+        if (auto it = m_abbrevs.find(n))
+            return *it;
+        else
+            return false;
+    }
+
+    optional<name> is_abbreviated(expr const & e) const {
+        if (auto it = m_inv_map.find(e))
+            return optional<name>(*it);
+        else
+            return optional<name>();
+    }
+};
+
+static name * g_class_name = nullptr;
+static std::string * g_key = nullptr;
+
+struct abbrev_config {
+    typedef abbrev_state  state;
+    typedef abbrev_entry  entry;
+    static void add_entry(environment const & env, io_state const &, state & s, entry const & e) {
+        s.add(env, e.first, e.second);
+    }
+    static name const & get_class_name() {
+        return *g_class_name;
+    }
+    static std::string const & get_serialization_key() {
+        return *g_key;
+    }
+    static void  write_entry(serializer & s, entry const & e) {
+        s << e.first << e.second;
+    }
+    static entry read_entry(deserializer & d) {
+        entry e;
+        d >> e.first >> e.second;
+        return e;
+    }
+    static optional<unsigned> get_fingerprint(entry const & e) {
+        return some(e.first.hash());
+    }
+};
+
+template class scoped_ext<abbrev_config>;
+typedef scoped_ext<abbrev_config> abbrev_ext;
+
+environment add_abbreviation(environment const & env, name const & n, bool parsing_only, bool persistent) {
+    return abbrev_ext::add_entry(env, get_dummy_ios(), abbrev_entry(n, parsing_only), persistent);
+}
+
+bool is_abbreviation(environment const & env, name const & n) {
+    abbrev_state const & s = abbrev_ext::get_state(env);
+    return s.is_abbreviation(n);
+}
+
+bool is_parsing_only_abbreviation(environment const & env, name const & n) {
+    abbrev_state const & s = abbrev_ext::get_state(env);
+    return s.is_parsing_only_abbreviation(n);
+}
+
+optional<name> is_abbreviated(environment const & env, expr const & e) {
+    abbrev_state const & s = abbrev_ext::get_state(env);
+    return s.is_abbreviated(e);
+}
+
+bool contains_abbreviations(environment const & env, expr const & e) {
+    abbrev_state const & s = abbrev_ext::get_state(env);
+    return static_cast<bool>(find(e, [&](expr const & e, unsigned) {
+                return is_constant(e) && s.is_abbreviation(const_name(e));
+            }));
+}
+
+struct expand_abbrev_fn : public replace_visitor {
+    environment const &  m_env;
+    abbrev_state const & m_state;
+
+    virtual expr visit_app(expr const & e) {
+        buffer<expr> args;
+        expr const & f = get_app_args(e, args);
+        expr new_f     = visit(f);
+        bool modified  = !is_eqp(f, new_f);
+        for (expr & arg : args) {
+            expr new_arg = visit(arg);
+            if (!is_eqp(arg, new_arg))
+                modified = true;
+            arg = new_arg;
+        }
+        expr r;
+        if (modified)
+            r = mk_app(new_f, args);
+        else
+            r = e;
+        if (is_constant(new_f) && m_state.is_abbreviation(const_name(new_f)))
+            r = *unfold_app(m_env, r);
+        return r;
+    }
+
+    virtual expr visit_constant(expr const & e) {
+        if (m_state.is_abbreviation(const_name(e)))
+            return instantiate_value_univ_params(m_env.get(const_name(e)), const_levels(e));
+        else
+            return e;
+    }
+
+    expand_abbrev_fn(environment const & env):
+        m_env(env),
+        m_state(abbrev_ext::get_state(env)) {
+    }
+};
+
+expr expand_abbreviations(environment const & env, expr const & e) {
+    if (!contains_abbreviations(env, e))
+        return e;
+    return expand_abbrev_fn(env)(e);
+}
+
+void initialize_abbreviation() {
+    g_class_name = new name("abbreviations");
+    g_key        = new std::string("abbrev");
+    abbrev_ext::initialize();
+}
+
+void finalize_abbreviation() {
+    abbrev_ext::finalize();
+    delete g_key;
+    delete g_class_name;
+}
+}
diff --git a/src/library/abbreviation.h b/src/library/abbreviation.h
new file mode 100644
index 000000000..75a2d3ded
--- /dev/null
+++ b/src/library/abbreviation.h
@@ -0,0 +1,19 @@
+/*
+Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+Released under Apache 2.0 license as described in the file LICENSE.
+
+Author: Leonardo de Moura
+*/
+#pragma once
+#include "kernel/environment.h"
+
+namespace lean {
+environment add_abbreviation(environment const & env, name const & n, bool parsing_only, bool persistent = true);
+bool is_abbreviation(environment const & env, name const & n);
+bool is_parsing_only_abbreviation(environment const & env, name const & n);
+optional<name> is_abbreviated(environment const & env, expr const & e);
+bool contains_abbreviations(environment const & env, expr const & e);
+expr expand_abbreviations(environment const & env, expr const & e);
+void initialize_abbreviation();
+void finalize_abbreviation();
+}
diff --git a/src/library/init_module.cpp b/src/library/init_module.cpp
index 1713f6e25..5b67d3713 100644
--- a/src/library/init_module.cpp
+++ b/src/library/init_module.cpp
@@ -35,6 +35,7 @@ Author: Leonardo de Moura
 #include "library/pp_options.h"
 #include "library/projection.h"
 #include "library/normalize.h"
+#include "library/abbreviation.h"
 
 namespace lean {
 void initialize_library_module() {
@@ -69,9 +70,11 @@ void initialize_library_module() {
     initialize_pp_options();
     initialize_projection();
     initialize_normalize();
+    initialize_abbreviation();
 }
 
 void finalize_library_module() {
+    finalize_abbreviation();
     finalize_normalize();
     finalize_projection();
     finalize_pp_options();