diff --git a/.github/workflows/check_file_import.yml b/.github/workflows/check_file_import.yml
new file mode 100644
index 00000000..d29335c7
--- /dev/null
+++ b/.github/workflows/check_file_import.yml
@@ -0,0 +1,22 @@
+on: 
+  push: 
+
+name: check file import
+
+jobs: 
+  check_file_import: 
+    name: check file import 
+    runs-on: ubuntu-latest
+    steps: 
+     - name: clean up
+       run: |
+        find . -name . -o -prune -exec rm -rf -- {} +
+
+    - uses: actions/checkout@v4
+  
+    - name: update HepLean.lean 
+        run: |
+          git ls-files 'HepLean/*.lean' | LC_ALL=C sort | sed 's/\.lean//;s,/,.,g;s/^/import /' > HepLean.lean
+
+    - name: check that all files are imported
+        run: git diff --exit-code
\ No newline at end of file
diff --git a/HepLean/AnomalyCancellation/Basic.lean b/HepLean/AnomalyCancellation/Basic.lean
index 4695374f..85932c31 100644
--- a/HepLean/AnomalyCancellation/Basic.lean
+++ b/HepLean/AnomalyCancellation/Basic.lean
@@ -4,13 +4,6 @@ Released under Apache 2.0 license.
 Authors: Joseph Tooby-Smith
 -/
 import HepLean.AnomalyCancellation.LinearMaps
-import Mathlib.Tactic.Polyrith
-import Mathlib.Tactic.Linarith
-import Mathlib.Tactic.FieldSimp
-import Mathlib.NumberTheory.FLT.Basic
-import Mathlib.Algebra.QuadraticDiscriminant
-import Mathlib.Algebra.Module.Basic
-import Mathlib.Algebra.Module.LinearMap.Basic
 /-!
 # Basic set up for anomaly cancellation conditions
 
diff --git a/HepLean/AnomalyCancellation/LinearMaps.lean b/HepLean/AnomalyCancellation/LinearMaps.lean
index 709c6e7c..8fe55723 100644
--- a/HepLean/AnomalyCancellation/LinearMaps.lean
+++ b/HepLean/AnomalyCancellation/LinearMaps.lean
@@ -14,6 +14,7 @@ quadratic and cubic equations.
 ## TODO
 
 Use definitions in `Mathlib4` for definitions where possible.
+In particular a HomogeneousQuadratic should be a map `V →ₗ[ℚ] V →ₗ[ℚ] ℚ`  etc.
 
 -/