# What are the main changes between ISO 31-11 and ISO 80000-2? (math notation standards)

The international standard that defines mathematical signs and symbols, ISO 31-11, was superseded in 2009 by ISO 80000-2. What are the main changes?

• I didn't know there was such a thing! – abnry Jan 31 '14 at 22:19
• @nayrb Yeah that's pretty convenient. Unfortunately the ISO 80000-2 is behind paywall, which is a very nice way to spread a standard... – Franck Dernoncourt Jan 31 '14 at 22:38
• I won't pay 140 CHF to help decide when to write $\phi$ and when $\varphi$. And I'll keep writing $\pi$ in italics anyway cause I don't know how to avoid it – Hagen von Eitzen Jan 31 '14 at 22:40
• I can't imagine why the very idea puts my back up. Yet, it does. Perhaps it's just too 1984-ish. – Jonathan Y. Jan 31 '14 at 22:57
• Personally I looked for international standards for math notation when I moved from France to the US. As some notations changed, e.g. an open interval is commonly written ]a, b[ in France vs. (a, b) in the US, I started getting interested in standard notations for at least the most common concepts. – Franck Dernoncourt Jan 31 '14 at 23:03

So I've got the document (160 USD for 40 pages!). Here is what it says in page iv:

The first edition cancels and replaces ISO 31-11:1992, which has been technically revised. The major technical changes from the previous standard are the following:

• Four clauses have been added, i.e. "Standard number sets and intervals", "Elementary geometry", "Combinatorics" and "Transforms".

Interestingly, it goes on saying that the standard's title "Quantities and units — Part 2: Mathematical signs and symbols to be used in the natural sciences and technology" should be renamed into "Quantities and units — Part 2: Mathematics".

Given the amount of copyright notices and other efforts to keep the standard from being diffused, I hope I don't get sued for quoting one sentence...

• What a complete waste of money, Frank! – Pedro Tamaroff May 31 '14 at 21:12
• I am upvoting this just because you paid that much money for the document. – naslundx May 31 '14 at 21:21
• Thanks, I just need to find a way to turn upvotes into USD and my investment will finally pay back :-) – Franck Dernoncourt Jun 1 '14 at 0:58
• I don't understand how something can become standard if it's hoarded at such an exorbitant price. – gen-z ready to perish Apr 8 at 6:40