You can copy operators into the text from here: ≠ , ≤ , ≥ , < , > , ⊇ , ∉ , ∈ , ∩ , ∪ , ⊂ , ⊃ , ∧ , ∨ , ∞ , ∖ ,):
More UTF-8 Math operators and here Tutorial