diff --git a/lisainstrument/shift_inversion_numpy.py b/lisainstrument/shift_inversion_numpy.py
index af70ce49fae3c574c987fa0089fe490f39329456..4bd90e9d63cef55ef042402edaa24ea4e4526644 100644
--- a/lisainstrument/shift_inversion_numpy.py
+++ b/lisainstrument/shift_inversion_numpy.py
@@ -204,7 +204,8 @@ class ShiftInverseNumpy:  # pylint: disable=too-few-public-methods
         Hence, :math:`f(l,d_l) = I[\delta U_k](-d_l) \approx \delta U(v_l - d_l)`.
 
         If the iteration converges, it converges to a solution
-        :math:`\delta \bar{V}_l = f(l,\delta \bar{V}_l) \approx \delta U(v_l - \delta\bar{V}_l) =  \delta U(u_l - \delta\bar{V}_l)`,
+        :math:`\delta \bar{V}_l = f(l,\delta \bar{V}_l)
+        \approx \delta U(v_l - \delta\bar{V}_l) =  \delta U(u_l - \delta\bar{V}_l)`,
         where we used the implicit convention that :math:`u_l = v_l`.
         This equation fulfilled for :math:`\delta\bar{V}_l` is indeed the one that
         needs to be fulfilled for the desired quantity :math:`\delta V_l`, which