space Ø emptyset ε Σ σ † × · ö oh-umlaut as in Gödel's － DASH ≤ ≤ ≥ ≥ ≠ ≠ ≦ <= (smaller) ≧ >= (smaller) ⊂ ⊂ SUBSET ⊃ ⊃ SUPERSET ⊆ ⊆ ⊇ ⊇ ≡ ≡ ∀ ∀ ∃ ∃ ∈ ∈ MEMBER ∏ ∏ ∑ ∑ ∞ ∞ ∧ ∧ ∨ ∨ ∩ ∩ (INTERSECTION) ∪ ∪ (UNION) ￢ ¬ ¬ 〚 [[ 〛 ]] ├ |- proves ╞ |= models ← ← ARROWS ↑ ↑ → → ↓ ↓ ↔ ↔ # #(sharp) " " " ∘ center o (COMPOSE) (also ￮) ● black dot … ellipsis – hyphen § § section