diff --git a/phino.cabal b/phino.cabal
--- a/phino.cabal
+++ b/phino.cabal
@@ -1,6 +1,6 @@
 cabal-version: 3.0
 name: phino
-version: 0.0.119
+version: 0.0.120
 license: MIT
 synopsis: Command-Line Manipulator of 𝜑-Calculus Expressions
 description: Please see the README on GitHub at <https://github.com/objectionary/phino#readme>
diff --git a/src/Rule.hs b/src/Rule.hs
--- a/src/Rule.hs
+++ b/src/Rule.hs
@@ -126,6 +126,7 @@
     notAsset (BiDelta _) = False
     notAsset (BiLambda _) = False
     notAsset (BiVoid AtRho) = False
+    notAsset (BiTau AtRho _) = False
     notAsset _ = True
 numToInt (Y.Literal num) _ = Just num
 numToInt _ _ = Nothing
diff --git a/src/XMIR.hs b/src/XMIR.hs
--- a/src/XMIR.hs
+++ b/src/XMIR.hs
@@ -485,10 +485,7 @@
           if null (cur C.$/ C.element (toName "o"))
             then pure ExRoot
             else throwIO (InvalidXMIRFormat "Application of 'Φ' is illegal in XMIR" cur)
-        "⊥" ->
-          if null (cur C.$/ C.element (toName "o"))
-            then pure ExTermination
-            else throwIO (InvalidXMIRFormat "Application of '⊥' is illegal in XMIR" cur)
+        "⊥" -> xmirToApplication ExTermination (cur C.$/ C.element (toName "o")) fqn
         'Φ' : '.' : rest -> xmirToExpression' ExRoot "Φ" rest cur fqn
         'ξ' : '.' : rest -> xmirToExpression' ExXi "ξ" rest cur fqn
         _ -> throwIO (InvalidXMIRFormat "The @base attribute must be either ['∅'|'Φ'] or start with ['Φ.'|'ξ.'|'.']" cur)