fix LaTeX typesetting

doc/tutorials/stdp_windows/stdp_windows.ipynb

@@ -69,13 +69,13 @@
     "To implement the kernel, we use two extra state variables to keep track of recent spiking activity. These could correspond to calcium concentration in biology. One presynaptic trace value and another postsynaptic trace value is used, for pre- and post spiking, respectively. These maintain a history of neuron spikes, being incremented by 1 whenever a spike is generated, and decaying back to zero exponentially; in other words, a convolution between the exponentially decaying kernel and the emitted spike train:\n",
     "\n",
     "\\begin{equation}\n",
-    "\\text{tr_pre} = K \\ast \\sum_i \\delta_{pre,i}\n",
+    "\\text{tr\\_pre} = K \\ast \\sum_i \\delta_{pre,i}\n",
     "\\end{equation}\n",
     "\n",
     "and\n",
     "\n",
     "\\begin{equation}\n",
-    "\\text{tr_post} = K \\ast \\sum_i \\delta_{post,i}\n",
+    "\\text{tr\\_post} = K \\ast \\sum_i \\delta_{post,i}\n",
     "\\end{equation}\n",
     "\n",
     "These are implemented in the NESTML model as follows:\n",
@@ -111,7 +111,7 @@
     "The update rule for facilitation:\n",
     "\n",
     "\\begin{equation}\n",
-    "\\Delta^+ w = \\lambda \\cdot (1 - w)^{\\mu+} \\cdot \\text{pre_trace}\n",
+    "\\Delta^+ w = \\lambda \\cdot (1 - w)^{\\mu+} \\cdot \\text{pre\\_trace}\n",
     "\\end{equation}\n",
     "\n",
     "In NESTML, this rule is written in the `onReceive` event handler block. Statements in this block will be executed when the event occurs: in this case, receiving a presynaptic spike. In NESTML, additional scaling with an absolute maximum weight ``Wmax`` is added.\n",
@@ -126,7 +126,7 @@
     "The update rule for depression :\n",
     "\n",
     "\\begin{equation}\n",
-    "\\Delta^- w = -\\alpha \\cdot \\lambda \\cdot w^{\\mu_-} \\cdot \\text{post_trace}\n",
+    "\\Delta^- w = -\\alpha \\cdot \\lambda \\cdot w^{\\mu_-} \\cdot \\text{post\\_trace}\n",
     "\\end{equation}\n",
     "\n",
     "```\n",