diff --git a/notebooks/RL1 - Markov Decision Processes.ipynb b/notebooks/RL1 - Markov Decision Processes.ipynb
index 27e0649..6309c87 100644
--- a/notebooks/RL1 - Markov Decision Processes.ipynb	
+++ b/notebooks/RL1 - Markov Decision Processes.ipynb	
@@ -699,7 +699,7 @@
     "\\end{align*}\n",
     "One writes $\\pi_t(A_t|S_t=s)$, or more simply $\\pi_t(\\cdot | s)$.  \n",
     "In a stationary Markovian policy, all decision rules are the same throughout time. Mathematically:  \n",
-    "$\\forall (t,t')\\in \\mathbb{N}^2, \\pi_t(A_t|S_t=s) = \\pi_t(A_{t'}|S_{t'}=s)$.  \n",
+    "$\\forall (t,t')\\in \\mathbb{N}^2, \\pi_t(A_t|S_t=s) = \\pi_t'(A_{t'}|S_{t'}=s)$.  \n",
     "This unique distribution is written $\\pi(\\cdot | s) = \\pi_t( \\cdot | s)$.\n",
     "</details>"
    ]