diff --git a/nixos/kblayouts/fox-compose.xcompose b/nixos/kblayouts/fox-compose.xcompose
index 0c0f4c82..07807bc9 100644
--- a/nixos/kblayouts/fox-compose.xcompose
+++ b/nixos/kblayouts/fox-compose.xcompose
@@ -122,6 +122,7 @@
 
 # Mathy stuffs
 <Multi_key> <n> <a> <b> <l> <a> : "∇"
+<Multi_key> <l> <a> <p> <l> <a> <c> <e> : "∆"
 <Multi_key> <c> <r> <o> <s> <s> : "⨯"
 <Multi_key> <v> <e> <c> : "⃗" # combining vector above last symbol
 <Multi_key> <d> <i> <f> : "∂"