\nshortparallelThe symbol \nshortparallel is used to denote that two lines or planes are not parallel to each other. It is the negation of the parallel relation, which is typically represented by the symbol \shortparallel.
Line AB is not parallel to line CD.
AB \nshortparallel CDPlane \alpha is not parallel to plane \beta.
\text{Plane } \alpha \nshortparallel \text{Plane } \betaLine l_1 is not parallel to line l_2.
l_1 \nshortparallel l_2