diff --git a/egison.cabal b/egison.cabal
--- a/egison.cabal
+++ b/egison.cabal
@@ -1,5 +1,5 @@
 Name:                egison
-Version:             4.0.2
+Version:             4.0.3
 Synopsis:            Programming language with non-linear pattern-matching against non-free data
 Description:
   An interpreter for Egison, a **pattern-matching-oriented**, purely functional programming language.
diff --git a/lib/math/common/functions.egi b/lib/math/common/functions.egi
--- a/lib/math/common/functions.egi
+++ b/lib/math/common/functions.egi
@@ -13,7 +13,7 @@
       then match x as termExpr with
         | #0 -> 1
         | #1 -> e
-        | mult $a #(i * pi) -> (-1) ^ a
+        | mult $a #(i * π) -> (-1) ^ a
         | _ -> `exp x
       else `exp x
 
diff --git a/lib/math/normalize.egi b/lib/math/normalize.egi
--- a/lib/math/normalize.egi
+++ b/lib/math/normalize.egi
@@ -119,7 +119,7 @@
   match term as mathExpr with
     | $a * #`exp #0 * $r -> a *' r
     | $a * #`exp #1 * $r -> a *' e *' r
-    | $a * #`exp (mult $x #(i * pi)) * $r -> a *' (-1) ^ x *' r
+    | $a * #`exp (mult $x #(i * π)) * $r -> a *' (-1) ^ x *' r
     | $a * #`exp $x ^ (?(>= 2) & $n) * $r ->
       rewriteRuleForExp (a *' exp (x * n) *' r)
     | $a * #`exp $x * #`exp $y * $r -> rewriteRuleForExp (a *' exp (x + y) *' r)
@@ -202,8 +202,8 @@
     f term :=
       match term as mathExpr with
         | _ * #`sin #0 * _ -> 0
-        | _ * #`sin (mult _ #pi) * _ -> 0
-        | $a * #`sin (mult $n #pi / #2) * $mr ->
+        | _ * #`sin (mult _ #π) * _ -> 0
+        | $a * #`sin (mult $n #π / #2) * $mr ->
           a *' (-1) ^ ((abs n - 1) / 2) *' mr
         | _ -> term
 
@@ -212,8 +212,8 @@
     f term :=
       match term as mathExpr with
         | $a * #`cos #0 * $mr -> a *' mr
-        | $a * #`cos (term $n [#pi]) * $mr -> a *' (-1) ^ abs n *' mr
-        | _ * #`cos (mult _ #pi / #2) * _ -> 0
+        | $a * #`cos (term $n [#π]) * $mr -> a *' (-1) ^ abs n *' mr
+        | _ * #`cos (mult _ #π / #2) * _ -> 0
         | _ -> term
 
 --