3-NIRVANA-user-guide/3.1-Code-basics.md

@@ -426,13 +426,6 @@ criteria which are
 
 -   derivatives-based (most important in practice):
 ![amr_deriv](uploads/25c608e1a335aca4242b34afb9e4ffeb/amr_deriv.png)  
-    $$\\left\[\\alpha\\frac{\|\\delta\\,\\!U\|}{\|U\|+U\_\\mathrm{ref}}+(1-\\alpha)
-    \\frac{\|\\delta\\,\\!^2U\|}{\|\\delta\\,\\!U\|+{\\rm FILTER}\\cdot(\|U\|+U\_\\mathrm{ref})}\\right\]
-    \\left(\\frac{\\delta\\,\\!x^{(l)}}{\\delta\\,\\!x^{(0)}}\\right)^{\\xi}
-    \\left\\{\\begin{array}{ll}
-    >\\mathcal{E}\_{U}  &\\exists U \\quad\\hbox{refinement}\\\\
-    <0.8\\mathcal{E}\_{U}  & \\forall U \\quad\\hbox{derefinement}\\\\
-    \\end{array}\\right.$$
 
     The criterion is applied to primary (or related) physical variables
     *U* ( = {𝜚, **m**, *e*, **B**, *C*<sub>*c*</sub>}). Undivided first