perturbation -> stability

Change of terminology. I want "perturbation" to refer to the phenomenon where "the boundary comes one column in"

Author: jw-allen

lib/panels.gi

@@ -52,7 +52,7 @@ InstallMethod(
         # Test for, and reject, syllables beside unstable ones.
         if IsZeroSyllable( sy ) then
             Error( "Cannot panellify from a zero syllable" );
-        elif PerturbationTermOfSyllable( sy ) = 0 then
+        elif StabilityTermOfSyllable( sy ) = 0 then
             Error( "Cannot panellify from a stable syllable" );
 
         # Otherwise, proceed.

lib/patchreps.gi

@@ -130,7 +130,7 @@ InstallMethod(
             #  (overquiver representatives of) components of commuativity
             #  relations. On one side (east or west), these have as northern
             #  component a virtual syllable (ie, a syllable with source/
-            #  length/perturbation tuple [i,0,0] for some target i of a commu-
+            #  length/stability tuple [i,0,0] for some target i of a commu-
             #  -tativity rel) and as southern component the associated trivial
             #  syllable (ie, [i,0,1]) as southern component. On the other side,
             #  both components are <zero_sy>
@@ -235,12 +235,12 @@ InstallMethod(
 
             # Second, we create those featuring exactly one 'pin boundary'.
             #  These also deserve special treatment, as any southern entry on
-            #  the nonboundary side must have perturbation term 1 (not 0).
+            #  the nonboundary side must have stability term 1 (not 0).
             # The patches will have the 'pin boundary' syllable in a northern
             #  component on one side; beneath it on that side goes <zero_sy>.
             #  On the other side, the northern component is any non-'pin bound-
             #  -ary' syllable with source <j>, and the southern component is
-            #  the <desc>-image thereof with perturbation term adjusted to 1:
+            #  the <desc>-image thereof with stability term adjusted to 1:
             #  here, <j> denotes the exchange partner of the source <i> of the
             #  'pin boundary' syllable. General theory ensures that this
             #  <desc>-image is never <zero_sy>. We write a local boolean func-
@@ -361,7 +361,7 @@ InstallMethod(
             # Lastly, create the patches that have exactly one "northern" comp-
             #  -onent featuring <zero_sy>. These syllables can be constructed
             #  by replacing a single trivial syllable (ie, a syllable whose
-            #  source/length/pertubation tuple is [i,0,1] for some vertex i) in
+            #  source/length/stability tuple is [i,0,1] for some vertex i) in
             #  a northern component by <zero_sy>.
 
             # {Is it possible to make this functionality part of the the
@@ -370,11 +370,11 @@ InstallMethod(
             is_triv := function( x )
                 local
                     path,   # Underlying path of <x>
-                    pert;   # Perturbation term of <x>
+                    stab;   # Stability term of <x>
                 path := UnderlyingPathOfSyllable( x );
-                pert := PerturbationTermOfSyllable( x );
+                stab := StabilityTermOfSyllable( x );
 
-                return ( IsQuiverVertex( path ) and ( pert = 1 ) );
+                return ( IsQuiverVertex( path ) and ( stab = 1 ) );
             end;
 
             triv_list := [];

lib/syllables.gd

@@ -1,5 +1,5 @@
 DeclareRepresentation( "IsSyllableRep", IsAttributeStoringRep,
- [ "path", "perturbation", "sb_alg" ] );
+ [ "path", "stability", "sb_alg" ] );
 
 DeclareAttribute( "SyllableFamilyOfSBAlg", IsSpecialBiserialAlgebra );
 DeclareAttribute( "SyllableSetOfSBAlg", IsSpecialBiserialAlgebra );
@@ -8,7 +8,7 @@ DeclareAttribute( "ZeroSyllableOfSBAlg", IsSpecialBiserialAlgebra );
 DeclareOperation( "Syllabify", [ IsPath, IsInt ] );
 
 DeclareOperation( "UnderlyingPathOfSyllable", [ IsSyllableRep ] );
-DeclareOperation( "PerturbationTermOfSyllable", [ IsSyllableRep ] );
+DeclareOperation( "StabilityTermOfSyllable", [ IsSyllableRep ] );
 
 DeclareProperty( "IsZeroSyllable", IsSyllableRep );
 DeclareProperty( "IsVirtualSyllable", IsSyllableRep );

lib/syllables.gi

@@ -24,7 +24,7 @@ InstallMethod(
     [ IsSyllableRep, IsSyllableRep ],
     function( sy1, sy2 )
         if ( sy1!.path = sy2!.path and
-         sy1!.perturbation = sy2!.perturbation and
+         sy1!.stability = sy2!.stability and
          sy1!.sb_alg = sy2!.sb_alg ) then
             return true;
         else
@@ -40,7 +40,7 @@ InstallMethod(
     [ IsSyllableRep, IsSyllableRep ],
     function( sy1, sy2 )
         local
-            ep1, ep2,       # Perturbation terms of <sy1> and <sy2>
+            ep1, ep2,       # Stability terms of <sy1> and <sy2>
             i1, i2,         # Sources of <path1> and <path2>
             len1, len2,     # Lengths of <path1> and <path2>
             path1, path2;   # Underlying paths of <sy1> and <sy2>
@@ -66,8 +66,8 @@ InstallMethod(
             i2 := SourceOfPath( path2 );
             len1 := LengthOfPath( path1 );
             len2 := LengthOfPath( path2 );
-            ep1 := sy1!.perturbation;
-            ep2 := sy2!.perturbation;
+            ep1 := sy1!.stability;
+            ep2 := sy2!.stability;
 
             return [ len1, i1, ep1 ] < [ len2, i2, ep2 ];
         fi;
@@ -84,7 +84,7 @@ InstallMethod(
             a_seq, b_seq,   # Integer and bit sequences of <source_enc>
             d_i,            # <i>th term <d_seq>
             d_seq,          # Bit sequence of <target_enc>
-            ep,             # Bit variable for perturbation
+            ep,             # Bit variable for stability
             i,              # Vertex variable
             l,              # Length variable
             obj,            # Object to be made into a syllable, or data therof
@@ -108,7 +108,7 @@ InstallMethod(
             # Create zero syllable
             obj := rec(
              path := Zero( oquiv ),
-             perturbation := fail,
+             stability := fail,
              sb_alg := sba
             );
 
@@ -154,7 +154,7 @@ InstallMethod(
                         if d_i <= l + ep then
                             obj := rec(
                              path := PathBySourceAndLength( i, l ),
-                             perturbation := ep,
+                             stability := ep,
                              sb_alg := sba
                              );
                             ObjectifyWithAttributes(
@@ -190,7 +190,7 @@ InstallMethod(
 
 InstallMethod(
     Syllabify,
-    "for a path and a perturbation term",
+    "for a path and a stability term",
     [ IsPath, IsInt ],
     function( path, int )
         local
@@ -208,7 +208,7 @@ InstallMethod(
             sba := SBAlgOfOverquiver( oquiv );
             syll_set := SyllableSetOfSBAlg( sba );
             matches := Filtered( syll_set,
-             x -> (x!.path = path) and (x!.perturbation = int)
+             x -> (x!.path = path) and (x!.stability = int)
              );
             if Length( matches ) <> 1 then
                 Error( "No syllables match this description!" );
@@ -270,11 +270,11 @@ InstallMethod(
 );
 
 InstallMethod(
-    PerturbationTermOfSyllable,
+    StabilityTermOfSyllable,
     "for syllables",
     [ IsSyllableRep ],
     function( sy )
-        return sy!.perturbation;
+        return sy!.stability;
     end
 );
 
@@ -286,7 +286,7 @@ InstallMethod(
         if HasIsStableSyllable( sy ) then
             return IsStableSyllable( sy );
         else
-            return ( PerturbationTermOfSyllable( sy ) = 0 );
+            return ( StabilityTermOfSyllable( sy ) = 0 );
         fi;
     end
 );
@@ -319,7 +319,7 @@ InstallMethod(
             a_i, b_i,       # <i>th terms of <a_seq> and <b_seq>
             a_seq, b_seq,   # Integer and bit sequences of source_encoding of
                             #  permissible data of <sba>
-            ep,             # Perturbation term of <sy>
+            ep,             # Stability term of <sy>
             i,              # Source of underlying path of <sy>
             len,            # Length of underlying path of <sy>
             sba,            # SB algebra to which <sy> belongs
@@ -339,7 +339,7 @@ InstallMethod(
 
             i := SourceOfPath( UnderlyingPathOfSyllable( sy ) );
             len := LengthOfPath( UnderlyingPathOfSyllable( sy ) );
-            ep := PerturbationTermOfSyllable( sy );
+            ep := StabilityTermOfSyllable( sy );
 
             a_i := a_seq.( String( i ) );
             b_i := b_seq.( String( i ) );
@@ -405,7 +405,7 @@ InstallMethod(
                         path1 := UnderlyingPathOfSyllable( sy );
                         i1 := SourceOfPath( path1 );
                         l1 := LengthOfPath( path1 );
-                        ep1 := PerturbationTermOfSyllable( sy );
+                        ep1 := StabilityTermOfSyllable( sy );
 
                         # Obtain <i1>th terms in permissble data of <sba>
                         a_seq := SourceEncodingOfPermDataOfSBAlg( sba )[1];
@@ -494,18 +494,18 @@ InstallMethod(
     function( sy )
         local
             path,           # Underlying path of <sy>
-            pert;           # Perturbation term of <sy>
+            stab;           # Stability term of <sy>
 
         if IsZeroSyllable( sy ) then
             return "( )";
 
         else
             # The returned string should look something like "( p, ep )"
             path := UnderlyingPathOfSyllable( sy );
-            pert := PerturbationTermOfSyllable( sy );
+            stab := StabilityTermOfSyllable( sy );
 
             return Concatenation(
-             "( ",  String( path ), ", ", String( pert ), " )"
+             "( ",  String( path ), ", ", String( stab ), " )"
              );
         fi;
     end
@@ -666,7 +666,7 @@ InstallMethod(
         if IsZeroSyllable( sy ) then
             TryNextMethod();
         else
-            # (Recall that virtual syllables have perturbation term 0 and so
+            # (Recall that virtual syllables have stability term 0 and so
             #  are stable syllables. This means they will (rightly) return
             #  <false> in the call below.)
 
@@ -684,7 +684,7 @@ InstallMethod(
         if IsZeroSyllable( sy ) then
             TryNextMethod();
         else
-            # (Recall that virtual syllables have perturbation term 0 and so
+            # (Recall that virtual syllables have stability term 0 and so
             #  are stable syllables. This means they will (rightly) return
             #  <false> in the call below.)