Logical Values and Operator Symbols

Q

What are correct ways to represent logical values and operators in MathML?

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A

Logical values, True and False, are not included in "ISO 80000-2 Quantities and Units - Mathematics" specifications. But they commonly represented as ⊤ and ⊥ in mathematical equations.

True - The logical true value should be expressed with the Down-Tack symbol ⊤ (U+22A4, ⊤ or ⊤).

False - The logical false value should be expressed with the Up-Tack symbol ⊥ (U+22A5, ⊥ or ⊥).

Relational operators should be represented according to "ISO 80000-2 Quantities and Units - Mathematics" specifications. Here are some examples:

And (Conjunction) - The and (conjunction) operation should be expressed with the Logical-And symbol ∧ (U+2227, ∧ or ∧). For example:

<math><mi>&#x22A4;</mi><mo>&#x2227;</mo><mi>&#x22A5;</mi>
  <mo>=</mo><mi>&#x22A5;</mi></math>
    ⊤∧⊥
      =⊥

Or (Disjunction) - The or (disjunction) operation should be expressed with the Logical-Or symbol ∨ (U+2228, &#x2228; or &or;). For example:

<math><mi>&#x22A4;</mi><mo>&#x2228;</mo><mi>&#x22A5;</mi>
  <mo>=</mo><mi>&#x22A4;</mi></math>
    ⊤∨⊥
      =⊤

Not (Negation) - The not (negation) operation should be expressed with the Logical-Not symbol ¬ (U+00AC, &#x00AC; or &not;). For example:

<math><mo>&#x00AC;</mo><mi>&#x22A5;</mi>
  <mo>=</mo><mi>&#x22A4;</mi></math>
    ¬⊥
      =⊤

 

⇒ Sets and Set Operations

⇐ Relational Operator Symbols

⇑ ISO 80000-2 Quantities and Units - Mathematics

⇑⇑ MathML (Mathematical Markup Language)

2026-10-17, ∼1770🔥, 0💬