diff --git a/lib/haskell/natural4/src/LS/BasicTypes.hs b/lib/haskell/natural4/src/LS/BasicTypes.hs
index a07b8554c..b9c86a150 100644
--- a/lib/haskell/natural4/src/LS/BasicTypes.hs
+++ b/lib/haskell/natural4/src/LS/BasicTypes.hs
@@ -80,7 +80,7 @@ data MyToken = Every | Party | TokAll
              | Empty | EOL
              | RuleMarker Int Text.Text
              | Expect | ScenarioTok
-             | TokLT | TokLTE | TokGT | TokGTE | TokIn | TokNotIn | TokEQ | TokAnd | TokOr | TokSum | TokProduct
+             | TokLT | TokLTE | TokGT | TokGTE | TokIn | TokNotIn | TokEQ | TokAnd | TokOr | TokSum | TokProduct | TokMin | TokMax
              | Notwithstanding | Despite | SubjectTo
              | Otherwise
              | SOF | EOF
@@ -243,11 +243,11 @@ toToken "§§§§§§"    = pure $ RuleMarker   6  "§"
 toToken "SCENARIO"  = pure ScenarioTok
 toToken "EXPECT"    = pure Expect
 toToken "<"         = pure TokLT
-toToken "MIN"       = pure TokLT;      toToken "MIN OF"    = pure TokLT
+toToken "MIN"       = pure TokMin;     toToken "MIN OF"    = pure TokMin
 toToken "=<"        = pure TokLTE
 toToken "<="        = pure TokLTE
 toToken ">"         = pure TokGT
-toToken "MAX"       = pure TokGT;      toToken "MAX OF"    = pure TokGT
+toToken "MAX"       = pure TokMax;     toToken "MAX OF"    = pure TokMax
 toToken ">="        = pure TokGTE
 toToken "="         = pure TokEQ
 toToken "&&"        = pure TokAnd
@@ -416,6 +416,8 @@ renderToken (RuleMarker n txt) = concat $ replicate n (Text.unpack txt)
 renderToken Semicolon = ";;"
 
 renderToken SubjectTo = "SUBJECT TO"
+renderToken TokMin = "MIN"
+renderToken TokMax = "MAX"
 renderToken TokSum = "SUM"
 renderToken TokProduct = "PRODUCT"
 renderToken FMap = "MAP"
diff --git a/lib/haskell/natural4/src/LS/Interpreter.hs b/lib/haskell/natural4/src/LS/Interpreter.hs
index 8d8db7853..dc4327464 100644
--- a/lib/haskell/natural4/src/LS/Interpreter.hs
+++ b/lib/haskell/natural4/src/LS/Interpreter.hs
@@ -325,6 +325,7 @@ getAttrTypesIn ct classname =
 
 -- | structure the rules as a graph.
 -- in the simple case, the graph is one or more trees, each rooted at a "top-level" rule which is not "used" by any another rule.
+
 -- if we walk the roots, we will sooner or later encounter all the decision elements relevant to each root.
 -- in a less simple case, the graph is cyclic! everything depends on everything else! but we can recognize that as an error condition.
 --
diff --git a/lib/haskell/natural4/src/LS/RelationalPredicates.hs b/lib/haskell/natural4/src/LS/RelationalPredicates.hs
index 356c2ec57..db363e314 100644
--- a/lib/haskell/natural4/src/LS/RelationalPredicates.hs
+++ b/lib/haskell/natural4/src/LS/RelationalPredicates.hs
@@ -238,6 +238,8 @@ tok2rel = choice
     , RPor      <$ pToken TokOr
     , RPsum     <$ pToken TokSum
     , RPproduct <$ pToken TokProduct
+    , RPmin     <$ pToken TokMin
+    , RPmax     <$ pToken TokMax
     , RPlt      <$ pToken TokLT    -- serves double duty as MinOflist when in RPnary position
     , RPlte     <$ pToken TokLTE
     , RPgt      <$ pToken TokGT    -- serves double duty as MaxOflist when in RPnary position
diff --git a/lib/haskell/natural4/src/LS/Types.hs b/lib/haskell/natural4/src/LS/Types.hs
index 22dc06440..5adb6396f 100644
--- a/lib/haskell/natural4/src/LS/Types.hs
+++ b/lib/haskell/natural4/src/LS/Types.hs
@@ -51,6 +51,7 @@ type BoolStructR = AA.OptionallyLabeledBoolStruct RelationalPredicate
 
 -- | the relations in a RelationalPredicate
 data RPRel = RPis | RPhas | RPeq | RPlt | RPlte | RPgt | RPgte | RPelem | RPnotElem | RPnot | RPand | RPor | RPsum | RPproduct | RPsubjectTo
+           | RPmin | RPmax
            | RPmap
            | RPTC TComparison -- ^ temporal constraint as part of a relational predicate; note there is a separate `TemporalConstraint` type.
   deriving (Eq, Ord, Show, Generic, ToJSON)
@@ -276,6 +277,7 @@ mkRpmt a = RPMT (MTT <$> a)
 mkRpmtLeaf :: [Text.Text] -> BoolStructR
 mkRpmtLeaf a = mkLeaf (mkRpmt a)
 
+-- | [TODO] figure out why there are two very similar functions, this and `rel2op`
 rel2txt :: RPRel -> Text.Text
 rel2txt RPis      = "IS"
 rel2txt RPhas     = "HAS" -- "relHas"
@@ -290,6 +292,8 @@ rel2txt RPnot     = "NOT"    -- "relNot"
 rel2txt RPand     = "&&"    -- "relAnd"
 rel2txt RPor      = "||"    -- "relOr"
 rel2txt RPmap     = "MAP"
+rel2txt RPmin     = "MIN"
+rel2txt RPmax     = "MAX"
 rel2txt RPsum     = "SUM"
 rel2txt RPproduct = "PRODUCT"
 rel2txt (RPTC TBefore) = "BEFORE"
@@ -298,6 +302,7 @@ rel2txt (RPTC TBy    ) = "BY"
 rel2txt (RPTC TOn)     = "ON"
 rel2txt (RPTC TVague)  = "ABOUT"
 
+-- | [TODO] figure out why there are two very similar functions, this and `rel2txt`
 rel2op :: RPRel -> Text.Text
 rel2op RPis      = "IS"
 rel2op RPhas     = ".?"
@@ -311,14 +316,7 @@ rel2op RPnotElem = "NOT IN"
 rel2op RPnot     = "NOT"
 rel2op RPand     = "&&"
 rel2op RPor      = "||"
-rel2op RPmap     = "MAP"
-rel2op RPsum     = "SUM"
-rel2op RPproduct = "PRODUCT"
-rel2op (RPTC TBefore) = "BEFORE"
-rel2op (RPTC TAfter ) = "AFTER"
-rel2op (RPTC TBy    ) = "BY"
-rel2op (RPTC TOn)     = "ON"
-rel2op (RPTC TVague)  = "ABOUT"
+rel2op x         = rel2txt x
 
 rp2mt :: RelationalPredicate -> MultiTerm
 rp2mt (RPParamText    pt)            = pt2multiterm pt