diff --git a/compose_rl/algorithms/online/model_methods.py b/compose_rl/algorithms/online/model_methods.py
index bdcec748..d68e5771 100644
--- a/compose_rl/algorithms/online/model_methods.py
+++ b/compose_rl/algorithms/online/model_methods.py
@@ -238,7 +238,7 @@ def policy_loss(
             logits=gen_logits,
         )
         assert token_entropies.shape == batch['action_mask'].shape, (
-            f'Token entropies shape {token_entropies.shape} does not match action mask shape {batch["action_mask"].shape}.',
+            f'Token entropies shape {token_entropies.shape} does not match action mask shape {batch['action_mask'].shape}.',
         )
         seq_entropies = utils.get_sequence_entropies(
             token_entropies=token_entropies,
diff --git a/compose_rl/utils/rlvr_utils.py b/compose_rl/utils/rlvr_utils.py
index 4d4c888b..cae862d7 100644
--- a/compose_rl/utils/rlvr_utils.py
+++ b/compose_rl/utils/rlvr_utils.py
@@ -3,6 +3,7 @@
 
 import logging
 import re
+import signal
 from typing import Any
 
 import sympy
@@ -70,34 +71,55 @@ def remove_boxed(s: str) -> str:
     return s.strip('{}')
 
 
+class timeout:
+
+    def __init__(self, seconds:int=1, error_message:str='Timeout'):
+        self.seconds = seconds
+        self.error_message = error_message
+
+    def handle_timeout(self, signum, frame):
+        raise TimeoutError(self.error_message)
+
+    def __enter__(self):
+        signal.signal(signal.SIGALRM, self.handle_timeout)
+        signal.alarm(self.seconds)
+
+    def __exit__(self, type, value, traceback):
+        signal.alarm(0)
+
+
 def is_equiv(x1: str, x2: str) -> bool:
     """Checks mathematical equivalence between two normalized LaTeX strings."""
     try:
-        try:
-            parsed_x1 = parse_latex(x1)
-            parsed_x2 = parse_latex(x2)
-        except (
-            sympy.parsing.latex.  # pyright: ignore[reportGeneralTypeIssues]
-            errors.LaTeXParsingError,
-            sympy.SympifyError,
-            TypeError,
-        ):
-            log.debug(f"couldn't parse one of {x1} or {x2}")
-            return False
-
-        try:
-            diff = parsed_x1 - parsed_x2  # pyright: ignore[reportOptionalOperand]
-        except TypeError:
-            log.debug(f"couldn't subtract {x1} and {x2}")
-            return False
-
-        try:
-            return sympy.simplify(diff) == 0
-        except ValueError:
-            log.debug(
-                f'Had some trouble simplifying when comparing {x1} and {x2}',
-            )
-            return False
+        with timeout(seconds=5):
+            try:
+                parsed_x1 = parse_latex(x1)
+                parsed_x2 = parse_latex(x2)
+            except (
+                sympy.parsing.latex.  # pyright: ignore[reportGeneralTypeIssues]
+                errors.LaTeXParsingError,
+                sympy.SympifyError,
+                TypeError,
+            ):
+                log.debug(f"couldn't parse one of {x1} or {x2}")
+                return False
+
+            try:
+                diff = parsed_x1 - parsed_x2  # pyright: ignore[reportOptionalOperand]
+            except TypeError:
+                log.debug(f"couldn't subtract {x1} and {x2}")
+                return False
+
+            try:
+                return sympy.simplify(diff) == 0
+            except ValueError:
+                log.debug(
+                    f'Had some trouble simplifying when comparing {x1} and {x2}',
+                )
+                return False
+    except TimeoutError:
+        log.debug(f"Timed out comparing {x1} and {x2}")
+        return False
     except ImportError as e:
         log.error(e)
         raise