Test an error

src/math_tools/README.md

@@ -5,5 +5,5 @@ This folder contains mathematical classes and functions.
 ## Utility tools
 
 The l\_norm\_tools.hpp file contains functions computing the infinity norm. For now, it computes the infinity norm of 
-- a double: $`\Vert x \Vert_{\infty} = x`$; 
+- a double: $\Vert x \Vert_{\infty} = x$; 
 - a coordinate: $`\Vert x \Vert_{\infty} = \max_{i} (|x_i|)`$.