Nonlinear operators might not be compatible with addition, i.e. we find arguments v3=v1+v2{\displaystyle v_{3}=v_{1}+v_{2}} with f(v3)≠f(v1)+f(v2){\displaystyle f(v_{3})\neq f(v_{1})+f(v_{2})}. This property can be condensed in f(v1+v2)≠f(v1)+f(v2){\displaystyle f(v_{1}+v_{2})\neq f(v_{1})+f(v_{2})} for some vectors v1,v2{\displaystyle v_{1},v_{2}}.
Own work
Stephan Kulla (User:Stephan Kulla)