small fix to the documentation

diff --git a/examples/step-37/doc/intro.dox b/examples/step-37/doc/intro.dox
index e60666c0d516d375c07d7ca70d8b281335353b6f..b691313549be6e64481fe256bff7bba0347927d7 100644 (file)
--- a/examples/step-37/doc/intro.dox
+++ b/examples/step-37/doc/intro.dox
@@ -362,7 +362,7 @@ interpolation operation over the completely regular data fields of the
 reference cell. We illustrate the process of complexity reduction in two space
 dimensions, but the same technique can be used in higher dimensions. On the
 reference cell, the basis functions are of the tensor product form
-$\phi(x,y,z) = \varphi_i(x) \varphi_j(y)$. The part of the matrix
+$\phi(x,y) = \varphi_i(x) \varphi_j(y)$. The part of the matrix
 <i>B</i><sub>ref_cell</sub> that computes the first component has the form
 $B_\mathrm{sub\_cell}^x = B_\mathrm{grad,x} \otimes B_\mathrm{val,y}$, where
 <i>B</i><sub>grad,x</sub> and <i>B</i><sub>val,y</sub> contain the evaluation