ISO 80000-2:2009

Overview

ISO 80000-2:2009 - "Quantities and units - Part 2: Mathematical signs and symbols to be used in the natural sciences and technology" provides standardized recommendations for mathematical notation used in science and engineering. Prepared by ISO/TC 12 in collaboration with IEC/TC 25, this part of the ISO 80000 series defines meanings, verbal equivalents and preferred typographic conventions for symbols, operators, functions and structures commonly used in the natural sciences and technology.

Key topics

ISO 80000-2:2009 covers a broad set of notation and presentation rules, including:

• Typography and font usage

  • Variables and running indices in italic; well-defined functions, operators and constants in Roman (upright) type (examples: sin, ln, e, π, i).
  • Rules for function arguments and when parentheses may be omitted.

• Logical operators and quantifiers

  • Symbols and verbal equivalents for conjunction, disjunction, negation, implication, equivalence, universal (∀) and existential (∃) quantifiers.

• Set theory and number sets

  • Notation for membership (∈), subsets (⊆, ⊂), unions, intersections, Cartesian products, empty set (∅), cardinality, and standard number sets (ℕ, ℤ, ℚ, ℝ).

• Specialized mathematical areas

  • Geometry, combinatorics, matrices, vectors and tensors, complex numbers, functions, exponential/logarithmic, circular/hyperbolic functions, transforms and special functions.

• Formatting and presentation rules

  • Preferred separators, handling of multi-line expressions (where to break lines), and guidance on consistent use of symbol styles to improve readability.

Practical applications

ISO 80000-2 is practical for anyone who needs consistent, unambiguous mathematical notation across technical documents:

• Researchers and academics preparing journal articles, theses and textbooks.
• Engineers and scientists writing technical reports, specifications or simulation documentation.
• Standards developers and technical writers ensuring consistency across international standards and cross-disciplinary documents.
• Publishers and journal editors adopting uniform notation and typesetting rules.
• Software developers and documentation teams producing scientific libraries, APIs and user manuals where notation must match printed materials.

Adopting ISO 80000-2 improves clarity, reduces misinterpretation of formulas, and supports international interoperability of technical content.

Related standards

ISO 80000-2 is part of the ISO 80000 series (Quantities and units). Relevant related parts include:

• ISO 80000-1 (General)
• Parts covering Space and time, Mechanics, Thermodynamics, Electromagnetism, Information science, and others.

Keywords: ISO 80000-2:2009, mathematical signs and symbols, quantities and units, notation standard, scientific notation, technical typography, international standard.