--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Implab/IPromiseBase.cs	Thu Feb 06 01:08:59 2014 +0400
@@ -0,0 +1,19 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace Implab {
+    public interface IPromiseBase: ICancellable {
+        /// <summary>
+        /// Check whereather the promise has no more than one dependent promise.
+        /// </summary>
+        bool IsExclusive {
+            get;
+        }
+
+        bool IsResolved { get; }
+
+        bool IsCancelled { get; }
+    }
+}