sort TrivialSector as trivial for any Sector

Author: ogauthe

NDTensors/src/lib/SymmetrySectors/src/sector_definitions/trivial.jl

@@ -1,5 +1,6 @@
 #
 # Trivial sector
+# acts as a trivial sector for any AbstractSector
 #
 
 using ...GradedAxes: GradedAxes
@@ -13,8 +14,6 @@ trivial(::Type{TrivialSector}) = TrivialSector()
 
 GradedAxes.dual(::TrivialSector) = TrivialSector()
 
-Base.isless(::TrivialSector, ::TrivialSector) = false  # bypass default that calls label
-
 # TrivialSector acts as trivial on any AbstractSector
 function fusion_rule(::NotAbelianStyle, ::TrivialSector, c::AbstractSector)
   return to_gradedrange(c)
@@ -23,7 +22,7 @@ function fusion_rule(::NotAbelianStyle, c::AbstractSector, ::TrivialSector)
   return to_gradedrange(c)
 end
 
-# abelian case: return Category
+# abelian case: return Sector
 fusion_rule(::AbelianStyle, c::AbstractSector, ::TrivialSector) = c
 fusion_rule(::AbelianStyle, ::TrivialSector, c::AbstractSector) = c
 fusion_rule(::AbelianStyle, ::TrivialSector, ::TrivialSector) = TrivialSector()
@@ -32,3 +31,8 @@ fusion_rule(::AbelianStyle, ::TrivialSector, ::TrivialSector) = TrivialSector()
 Base.:(==)(c::AbstractSector, ::TrivialSector) = istrivial(c)
 Base.:(==)(::TrivialSector, c::AbstractSector) = istrivial(c)
 Base.:(==)(::TrivialSector, ::TrivialSector) = true
+
+# sorts as trivial for any Sector
+Base.isless(c::AbstractSector, ::TrivialSector) = c < trivial(c)
+Base.isless(::TrivialSector, c::AbstractSector) = trivial(c) < c
+Base.isless(::TrivialSector, ::TrivialSector) = false  # bypass default that calls label