diff --git a/src/api/dotnet/AST.cs b/src/api/dotnet/AST.cs
index 2c4c964df..7bc4f6dfb 100644
--- a/src/api/dotnet/AST.cs
+++ b/src/api/dotnet/AST.cs
@@ -149,6 +149,14 @@ namespace Microsoft.Z3
             }
         }
 
+        /// <summary>
+        /// Indicates whether the AST is an application
+        /// </summary>
+        public bool IsApp
+        {
+            get { return this.ASTKind == Z3_ast_kind.Z3_APP_AST; }
+        }
+
         /// <summary>
         /// Indicates whether the AST is a BoundVariable
         /// </summary>
diff --git a/src/api/dotnet/Expr.cs b/src/api/dotnet/Expr.cs
index 9f5c04f0b..b2927e2c3 100644
--- a/src/api/dotnet/Expr.cs
+++ b/src/api/dotnet/Expr.cs
@@ -215,7 +215,7 @@ namespace Microsoft.Z3
         /// </summary>
         public bool IsConst
         {
-            get { return IsExpr && NumArgs == 0 && FuncDecl.DomainSize == 0; }
+            get { return IsApp && NumArgs == 0 && FuncDecl.DomainSize == 0; }
         }
         #endregion