Renamed theorem "not_not" to "remove_double_negation" to prevent naming...

Renamed theorem "not_not" to "remove_double_negation" to prevent naming conflicts with section ints.

Sparkle/Tools/Sections/tautology.sec

@@ -18,7 +18,6 @@ SECTION DEFINES:
   THEOREM implies_x_true           : (ALL P {{P -> TRUE} <-> TRUE})
   THEOREM invert_implies           : (ALL P (ALL Q {{P -> Q} <-> {~Q -> ~P}}))
   THEOREM not_false                : {~FALSE <-> TRUE}
-  THEOREM not_not                  : (ALL P {~~P <-> P})
   THEOREM not_true                 : {~TRUE <-> FALSE}
   THEOREM or_false_x               : (ALL P {{FALSE \/ P} <-> P})
   THEOREM or_not_left              : (ALL P (ALL Q {~P -> {{P \/ Q} <-> Q}}))
@@ -27,6 +26,7 @@ SECTION DEFINES:
   THEOREM or_x_false               : (ALL P {{P \/ FALSE} <-> P})
   THEOREM or_x_true                : (ALL P {{P \/ TRUE} <-> TRUE})
   THEOREM reflexive_implies        : (ALL P {{P -> P} <-> TRUE})
+  THEOREM remove_double_negation   : (ALL P {~~P <-> P})
   THEOREM split_iff                : (ALL P (ALL Q {{P <-> Q} <-> {{P -> Q} /\ {Q -> P}}}))
   THEOREM symmetric_and            : (ALL P (ALL Q {{P /\ Q} <-> {Q /\ P}}))
   THEOREM symmetric_or             : (ALL P (ALL Q {{P \/ Q} <-> {Q \/ P}}))
@@ -299,20 +299,6 @@ PROOF:
      Contradiction.
      ExFalso H2.
 
-THEOREM:
-  not_not
-DEPENDS:
-  
-PROOF:
-  Introduce P.
-  SplitIff.
-  1. Introduce H1.
-     Contradiction.
-     Absurd H1 H2.
-  2. Introduce H1.
-     Contradiction.
-     Absurd H1 H2.
-
 THEOREM:
   not_true
 DEPENDS:
@@ -423,6 +409,20 @@ PROOF:
   2. Introduce H1 H2.
      Exact H2.
 
+THEOREM:
+  remove_double_negation
+DEPENDS:
+  
+PROOF:
+  Introduce P.
+  SplitIff.
+  1. Introduce H1.
+     Contradiction.
+     Absurd H1 H2.
+  2. Introduce H1.
+     Contradiction.
+     Absurd H1 H2.
+
 THEOREM:
   split_iff
 DEPENDS: