fix test point definition backslach problem

Author: jonathanschilling

article/abscab_Methods.tex

@@ -750,7 +750,7 @@ \subsection{Verification Method}
 consists of the combinations of all test knots along the $\rho'$ axis
 with all test knots along the $z'$ axis.
 Let $T_{\rho'}$ ($T_{z'}$) be the set of knots along the $\rho'$ ($z'$) axis to test the formulation on.
-Then $T = T_{\rho'} \otimes T_{z'} \\ T_\mathrm{cc}$ is the set of test point coordinates
+Then $T = T_{\rho'} \otimes T_{z'} \textbackslash T_\mathrm{cc}$ is the set of test point coordinates
 where $\otimes$ is the cartesian product of two sets
 and $T_\mathrm{cc}$ is the subset of points from $T_{\rho'} \otimes T_{z'}$ that are located exactly on the current carrier.
 First, the choice of test points for testing the implementations