Union (∪) and Intersection (∩) symbols in LaTeX can be produced via the \cup and \cap definitions while in math mode. No extra packages are required to use these symbols.

For example:

Let $L_C = L_A \cap (L_B \cup L_C)$

will produce:

  1. Adel Najafi Ark says:

    $L_{C} = L_{A} \cap (L_{B} \cup L_{C})$
    is true