diff --git a/lf-current/Lists.v b/lf-current/Lists.v
index b1c2ce49..741f4e47 100644
--- a/lf-current/Lists.v
+++ b/lf-current/Lists.v
@@ -1018,4 +1018,4 @@ Inductive baz : Type :=
Definition manual_grade_for_baz_num_elts : option (nat*string) := None.
(** [] *)
-(* Sat Jan 26 15:14:45 UTC 2019 *)
+(* Sun Feb 17 18:24:11 UTC 2019 *)
diff --git a/lf-current/ListsTest.v b/lf-current/ListsTest.v
index 0f8df109..1af629df 100644
--- a/lf-current/ListsTest.v
+++ b/lf-current/ListsTest.v
@@ -473,4 +473,4 @@ idtac "---------- rev_injective ---------".
idtac "MANUAL".
Abort.
-(* Sat Jan 26 15:14:49 UTC 2019 *)
+(* Sun Feb 17 18:24:16 UTC 2019 *)
diff --git a/lf-current/Logic.html b/lf-current/Logic.html
index 1fc1de93..2222da3d 100644
--- a/lf-current/Logic.html
+++ b/lf-current/Logic.html
@@ -17,7 +17,7 @@
diff --git a/lf-current/Logic.v b/lf-current/Logic.v
index 9667f778..7b6a1f8e 100644
--- a/lf-current/Logic.v
+++ b/lf-current/Logic.v
@@ -1389,4 +1389,4 @@ Definition implies_to_or := forall P Q:Prop,
[] *)
-(* Sat Jan 26 15:14:45 UTC 2019 *)
+(* Sun Feb 17 18:24:12 UTC 2019 *)
diff --git a/lf-current/LogicTest.v b/lf-current/LogicTest.v
index 5856ab32..f6f55267 100644
--- a/lf-current/LogicTest.v
+++ b/lf-current/LogicTest.v
@@ -390,4 +390,4 @@ idtac "---------- not_exists_dist ---------".
Print Assumptions not_exists_dist.
Abort.
-(* Sat Jan 26 15:14:52 UTC 2019 *)
+(* Sun Feb 17 18:24:19 UTC 2019 *)
diff --git a/lf-current/Maps.html b/lf-current/Maps.html
index 80668822..7fd1e6ad 100644
--- a/lf-current/Maps.html
+++ b/lf-current/Maps.html
@@ -17,7 +17,7 @@
diff --git a/lf-current/Maps.v b/lf-current/Maps.v
index 076a578a..a07fefa8 100644
--- a/lf-current/Maps.v
+++ b/lf-current/Maps.v
@@ -341,4 +341,4 @@ Proof.
apply t_update_permute.
Qed.
-(* Sat Jan 26 15:14:46 UTC 2019 *)
+(* Sun Feb 17 18:24:12 UTC 2019 *)
diff --git a/lf-current/MapsTest.v b/lf-current/MapsTest.v
index 3e78b902..d9e35c3b 100644
--- a/lf-current/MapsTest.v
+++ b/lf-current/MapsTest.v
@@ -75,4 +75,4 @@ idtac "".
idtac "********** Advanced **********".
Abort.
-(* Sat Jan 26 15:14:55 UTC 2019 *)
+(* Sun Feb 17 18:24:22 UTC 2019 *)
diff --git a/lf-current/Poly.html b/lf-current/Poly.html
index db8e6d40..9a85abbf 100644
--- a/lf-current/Poly.html
+++ b/lf-current/Poly.html
@@ -17,7 +17,7 @@
diff --git a/lf-current/Poly.v b/lf-current/Poly.v
index 28e7c702..bba7f044 100644
--- a/lf-current/Poly.v
+++ b/lf-current/Poly.v
@@ -1060,4 +1060,4 @@ End Church.
End Exercises.
-(* Sat Jan 26 15:14:45 UTC 2019 *)
+(* Sun Feb 17 18:24:11 UTC 2019 *)
diff --git a/lf-current/PolyTest.v b/lf-current/PolyTest.v
index 33a8e8d6..db6f5ba3 100644
--- a/lf-current/PolyTest.v
+++ b/lf-current/PolyTest.v
@@ -421,4 +421,4 @@ idtac "---------- Exercises.Church.exp_3 ---------".
Print Assumptions Exercises.Church.exp_3.
Abort.
-(* Sat Jan 26 15:14:50 UTC 2019 *)
+(* Sun Feb 17 18:24:17 UTC 2019 *)
diff --git a/lf-current/Postscript.html b/lf-current/Postscript.html
index ca6644df..3ac666d6 100644
--- a/lf-current/Postscript.html
+++ b/lf-current/Postscript.html
@@ -17,7 +17,7 @@
diff --git a/lf-current/Postscript.v b/lf-current/Postscript.v
index f250cfb4..a5d4139b 100644
--- a/lf-current/Postscript.v
+++ b/lf-current/Postscript.v
@@ -81,4 +81,4 @@
https://deepspec.org/event/dsss17/index.html
*)
-(* Sat Jan 26 15:14:46 UTC 2019 *)
+(* Sun Feb 17 18:24:13 UTC 2019 *)
diff --git a/lf-current/PostscriptTest.v b/lf-current/PostscriptTest.v
index f949d1cf..0a2e34bc 100644
--- a/lf-current/PostscriptTest.v
+++ b/lf-current/PostscriptTest.v
@@ -44,4 +44,4 @@ idtac "".
idtac "********** Advanced **********".
Abort.
-(* Sat Jan 26 15:15:05 UTC 2019 *)
+(* Sun Feb 17 18:24:32 UTC 2019 *)
diff --git a/lf-current/Preface.html b/lf-current/Preface.html
index c49be78f..19888677 100644
--- a/lf-current/Preface.html
+++ b/lf-current/Preface.html
@@ -17,7 +17,7 @@
diff --git a/lf-current/Preface.v b/lf-current/Preface.v
index e00cdcb2..f8a975b1 100644
--- a/lf-current/Preface.v
+++ b/lf-current/Preface.v
@@ -307,4 +307,4 @@
(National Science Foundation)在 NSF 科研赞助 1521523 号
_'深度规范科学'_ 下提供支持。 *)
-(* Sat Jan 26 15:14:44 UTC 2019 *)
+(* Sun Feb 17 18:24:11 UTC 2019 *)
diff --git a/lf-current/PrefaceTest.v b/lf-current/PrefaceTest.v
index f5216847..17356654 100644
--- a/lf-current/PrefaceTest.v
+++ b/lf-current/PrefaceTest.v
@@ -44,4 +44,4 @@ idtac "".
idtac "********** Advanced **********".
Abort.
-(* Sat Jan 26 15:14:47 UTC 2019 *)
+(* Sun Feb 17 18:24:13 UTC 2019 *)
diff --git a/lf-current/ProofObjects.html b/lf-current/ProofObjects.html
index 8cbbc502..92089204 100644
--- a/lf-current/ProofObjects.html
+++ b/lf-current/ProofObjects.html
@@ -17,7 +17,7 @@
diff --git a/lf-current/ProofObjects.v b/lf-current/ProofObjects.v
index 88b91854..e1876a2a 100644
--- a/lf-current/ProofObjects.v
+++ b/lf-current/ProofObjects.v
@@ -531,4 +531,4 @@ End MyEquality.
略会将这个事实加入到上下文中。 *)
-(* Sat Jan 26 15:14:46 UTC 2019 *)
+(* Sun Feb 17 18:24:12 UTC 2019 *)
diff --git a/lf-current/ProofObjectsTest.v b/lf-current/ProofObjectsTest.v
index 113a272f..3e9040c2 100644
--- a/lf-current/ProofObjectsTest.v
+++ b/lf-current/ProofObjectsTest.v
@@ -85,4 +85,4 @@ idtac "".
idtac "********** Advanced **********".
Abort.
-(* Sat Jan 26 15:14:56 UTC 2019 *)
+(* Sun Feb 17 18:24:23 UTC 2019 *)
diff --git a/lf-current/Rel.html b/lf-current/Rel.html
index f8ff3562..4fb1467f 100644
--- a/lf-current/Rel.html
+++ b/lf-current/Rel.html
@@ -17,7 +17,7 @@
diff --git a/lf-current/Rel.v b/lf-current/Rel.v
index be491428..40d69af5 100644
--- a/lf-current/Rel.v
+++ b/lf-current/Rel.v
@@ -356,4 +356,4 @@ Proof.
(* 请在此处解答 *) Admitted.
(** [] *)
-(* Sat Jan 26 15:14:46 UTC 2019 *)
+(* Sun Feb 17 18:24:12 UTC 2019 *)
diff --git a/lf-current/RelTest.v b/lf-current/RelTest.v
index eceadf04..1d57432c 100644
--- a/lf-current/RelTest.v
+++ b/lf-current/RelTest.v
@@ -44,4 +44,4 @@ idtac "".
idtac "********** Advanced **********".
Abort.
-(* Sat Jan 26 15:14:58 UTC 2019 *)
+(* Sun Feb 17 18:24:25 UTC 2019 *)
diff --git a/lf-current/Tactics.html b/lf-current/Tactics.html
index d034af32..b0f2b77d 100644
--- a/lf-current/Tactics.html
+++ b/lf-current/Tactics.html
@@ -17,7 +17,7 @@
diff --git a/lf-current/Tactics.v b/lf-current/Tactics.v
index 809c4f4e..fe570cb6 100644
--- a/lf-current/Tactics.v
+++ b/lf-current/Tactics.v
@@ -1050,4 +1050,4 @@ Proof. (* 请在此处解答 *) Admitted.
-(* Sat Jan 26 15:14:45 UTC 2019 *)
+(* Sun Feb 17 18:24:11 UTC 2019 *)
diff --git a/lf-current/TacticsTest.v b/lf-current/TacticsTest.v
index cb7b2e5a..78860bde 100644
--- a/lf-current/TacticsTest.v
+++ b/lf-current/TacticsTest.v
@@ -219,4 +219,4 @@ idtac "---------- existsb_existsb' ---------".
Print Assumptions existsb_existsb'.
Abort.
-(* Sat Jan 26 15:14:51 UTC 2019 *)
+(* Sun Feb 17 18:24:18 UTC 2019 *)
diff --git a/lf-current/coqindex.html b/lf-current/coqindex.html
index 3262ae1a..43466505 100644
--- a/lf-current/coqindex.html
+++ b/lf-current/coqindex.html
@@ -17,7 +17,7 @@