Update app.py

app.py

@@ -232,7 +232,7 @@ with gr.Blocks(title="Hull-White Interest Rate Model Dashboard") as demo:
     
     This interactive dashboard allows actuaries and financial professionals to explore the Hull-White short rate model:
     
-    **dr(t) = (θ(t) - ar(t))dt + σdW**
+    **$$dr(t) = (θ(t) - ar(t))dt + σdW$$**
     
     Adjust the parameters below to see how they affect the interest rate simulations and convergence properties.
     """)