diff --git a/src/frontends/lean/parse_table.cpp b/src/frontends/lean/parse_table.cpp
index 3358f19f1..0aad72210 100644
--- a/src/frontends/lean/parse_table.cpp
+++ b/src/frontends/lean/parse_table.cpp
@@ -359,10 +359,6 @@ static bool is_simple(unsigned num, transition const * ts) {
     return std::all_of(ts, ts+num, [](transition const & t) { return t.is_simple(); });
 }
 
-bool is_safe_ascii(unsigned num, transition const * ts) {
-    return std::all_of(ts, ts+num, [](transition const & t) { return t.is_safe_ascii(); });
-}
-
 /** \brief Given \c a, an expression that is the denotation of an expression, if \c a is a variable,
     then use the actions in the transitions \c ts to expand \c a. The idea is to produce a head symbol
     we can use to decide whether the notation should be considered during pretty printing.
diff --git a/src/frontends/lean/parse_table.h b/src/frontends/lean/parse_table.h
index f55861d5c..c7d04f04d 100644
--- a/src/frontends/lean/parse_table.h
+++ b/src/frontends/lean/parse_table.h
@@ -83,6 +83,8 @@ public:
     /** \brief Return true iff the action is not Ext or LuaExt */
     bool is_simple() const;
 };
+inline bool operator==(action const & a1, action const & a2) { return a1.is_equal(a2); }
+inline bool operator!=(action const & a1, action const & a2) { return !a1.is_equal(a2); }
 
 action mk_skip_action();
 action mk_expr_action(unsigned rbp = 0);
@@ -108,8 +110,12 @@ public:
     bool is_simple() const { return m_action.is_simple(); }
     bool is_safe_ascii() const { return m_token.is_safe_ascii(); }
 };
-
-bool is_safe_ascii(unsigned num, transition const * ts);
+inline bool operator==(transition const & t1, transition const & t2) {
+    return t1.get_token() == t2.get_token() && t1.get_action() == t2.get_action();
+}
+inline bool operator!=(transition const & t1, transition const & t2) {
+    return !(t1 == t2);
+}
 
 /** \brief Apply \c f to expressions embedded in the given transition */
 transition replace(transition const & t, std::function<expr(expr const &)> const & f);
diff --git a/src/frontends/lean/parser_config.cpp b/src/frontends/lean/parser_config.cpp
index 1944d3bd0..86de01edc 100644
--- a/src/frontends/lean/parser_config.cpp
+++ b/src/frontends/lean/parser_config.cpp
@@ -30,7 +30,7 @@ notation_entry replace(notation_entry const & e, std::function<expr(expr const &
 
 notation_entry::notation_entry():m_kind(notation_entry_kind::NuD) {}
 notation_entry::notation_entry(notation_entry const & e):
-    m_kind(e.m_kind), m_expr(e.m_expr), m_overload(e.m_overload) {
+    m_kind(e.m_kind), m_expr(e.m_expr), m_overload(e.m_overload), m_safe_ascii(e.m_safe_ascii) {
     if (is_numeral())
         new (&m_num) mpz(e.m_num);
     else
@@ -41,13 +41,14 @@ notation_entry::notation_entry(bool is_nud, list<transition> const & ts, expr co
     m_kind(is_nud ? notation_entry_kind::NuD : notation_entry_kind::LeD),
     m_expr(e), m_overload(overload) {
     new (&m_transitions) list<transition>(ts);
+    m_safe_ascii = std::all_of(ts.begin(), ts.end(), [](transition const & t) { return t.is_safe_ascii(); });
 }
 notation_entry::notation_entry(notation_entry const & e, bool overload):
     notation_entry(e) {
     m_overload = overload;
 }
 notation_entry::notation_entry(mpz const & val, expr const & e, bool overload):
-    m_kind(notation_entry_kind::Numeral), m_expr(e), m_overload(overload) {
+    m_kind(notation_entry_kind::Numeral), m_expr(e), m_overload(overload), m_safe_ascii(true) {
     new (&m_num) mpz(val);
 }
 
@@ -58,6 +59,15 @@ notation_entry::~notation_entry() {
         m_transitions.~list<transition>();
 }
 
+bool operator==(notation_entry const & e1, notation_entry const & e2) {
+    if (e1.kind() != e2.kind() || e1.overload() != e2.overload() || e1.get_expr() != e2.get_expr())
+        return false;
+    if (e1.is_numeral())
+        return e1.get_num() == e2.get_num();
+    else
+        return e1.get_transitions() == e2.get_transitions();
+}
+
 struct token_state {
     token_table m_table;
     token_state() { m_table = mk_default_token_table(); }
@@ -183,9 +193,12 @@ transition read_transition(deserializer & d) {
 
 struct notation_state {
     typedef rb_map<mpz, list<expr>, mpz_cmp_fn> num_map;
+    typedef head_map<notation_entry>            head_to_entries;
     parse_table      m_nud;
     parse_table      m_led;
     num_map          m_num_map;
+    head_to_entries  m_inv_map;
+
     notation_state() {
         m_nud = get_builtin_nud_table();
         m_led = get_builtin_led_table();
@@ -198,18 +211,28 @@ struct notation_config {
     static name * g_class_name;
     static std::string * g_key;
 
+    static void updt_inv_map(state & s, head_index const & idx, entry const & e) {
+        s.m_inv_map.insert(idx, e);
+    }
+
     static void add_entry(environment const &, io_state const &, state & s, entry const & e) {
         buffer<transition> ts;
         switch (e.kind()) {
         case notation_entry_kind::NuD:
             to_buffer(e.get_transitions(), ts);
+            if (auto idx = get_head_index(ts.size(), ts.data(), e.get_expr()))
+                updt_inv_map(s, *idx, e);
             s.m_nud = s.m_nud.add(ts.size(), ts.data(), e.get_expr(), e.overload());
             break;
         case notation_entry_kind::LeD:
             to_buffer(e.get_transitions(), ts);
+            if (auto idx = get_head_index(ts.size(), ts.data(), e.get_expr()))
+                updt_inv_map(s, *idx, e);
             s.m_led = s.m_led.add(ts.size(), ts.data(), e.get_expr(), e.overload());
             break;
         case notation_entry_kind::Numeral:
+            if (!is_var(e.get_expr()))
+                updt_inv_map(s, head_index(e.get_expr()), e);
             if (!e.overload()) {
                 s.m_num_map.insert(e.get_num(), list<expr>(e.get_expr()));
             } else if (auto it = s.m_num_map.find(e.get_num())) {
@@ -308,6 +331,13 @@ list<expr> get_mpz_notation(environment const & env, mpz const & n) {
     }
 }
 
+list<notation_entry> get_notation_entries(environment const & env, head_index const & idx) {
+    if (auto it = notation_ext::get_state(env).m_inv_map.find(idx))
+        return *it;
+    else
+        return list<notation_entry>();
+}
+
 environment overwrite_notation(environment const & env, name const & n) {
     environment r = env;
     bool found = false;
diff --git a/src/frontends/lean/parser_config.h b/src/frontends/lean/parser_config.h
index 67bdf85e6..1bb13db63 100644
--- a/src/frontends/lean/parser_config.h
+++ b/src/frontends/lean/parser_config.h
@@ -29,6 +29,7 @@ class notation_entry {
     };
     expr                 m_expr;
     bool                 m_overload;
+    bool                 m_safe_ascii;
 public:
     notation_entry();
     notation_entry(notation_entry const & e);
@@ -43,7 +44,12 @@ public:
     mpz const & get_num() const { lean_assert(is_numeral()); return m_num; }
     expr const & get_expr() const { return m_expr; }
     bool overload() const { return m_overload; }
+    bool is_safe_ascii() const { return m_safe_ascii; }
 };
+bool operator==(notation_entry const & e1, notation_entry const & e2);
+inline bool operator!=(notation_entry const & e1, notation_entry const & e2) {
+    return !(e1 == e2);
+}
 
 /** \brief Apply \c f to expressions embedded in the notation entry */
 notation_entry replace(notation_entry const & e, std::function<expr(expr const &)> const & f);
@@ -75,6 +81,13 @@ environment add_mpz_notation(environment const & env, mpz const & n, expr const
 */
 list<expr> get_mpz_notation(environment const & env, mpz const & n);
 
+/** \brief Return the notation declaration that start with a given head symbol.
+
+    \remark Notation declarations that contain C++ and Lua actions are not indexed.
+    Thus, they are to included in the result.
+*/
+list<notation_entry> get_notation_entries(environment const & env, head_index const & idx);
+
 void initialize_parser_config();
 void finalize_parser_config();
 }