You can copy operators into the text from here: ≠ , ≤ , ≥ , < , > , ⊇ , ⊆ , ∉ , ∈ , ∩ , ∪ , Ø , ⊂ , ⊃ , ∧ , ∨ , ∀ , ∃ , ⇒ , ⇔ , ¬ , ∞ , ∖ , ∣ , ∤ ):
More UTF-8 Math operators and here Tutorial