[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

**To**:*math-font-discuss@cogs.susx.ac.uk***Subject**:**Re: integrals****From**:*jeremy@cs.aukuni.ac.nz (Jeremy Gibbons)***Date**: 07 Aug 1993 16:50:36 +1200

> >Can somebody tell me why there is a small integral in cmex, and in cmsy. > >\int refers to the one in cmex. > > It's used in areas of mathematics where integration is seen as a > function from a set to a number, so: > \[ > \smallint\{e_i \mid i \in I} > \] > rather than: > \[ > \int_{i \in I} e_i > \] > Similarly, some mathematicians use \Sigma and \Pi rather than \sum and > \prod. (Jeremy, have you got references for this usage, this is your > sort of field?) I'm not sure I understand. \sum and \prod produce a big sigma and pi, respectively, don't they? Are you referring to the "Eindhoven Quantifer Notation", which uses $(\Sigma i \mathbin{:} 0 \le i < n \mathbin{:} i^2)$ for the sum of the squares of the first $n$ naturals? If so, you could see Dijkstra & Feijen, "A Method of Programming" (Addison-Wesley, 1988), but they actually use an uppercase "S" instead of a Sigma because it is "typewritten". (Looks awful, too.) Anne Kaldewaij's "Programming: The Derivation of Algorithms: (Prentice Hall, 1990) does use a Sigma, though. Doesn't apply to integrals, though. (Can you integrate over countable sets? I've only ever seen it done over reals or complex nos...) Jeremy

- Prev by Date:
**Re: SYMBOLS - operators** - Next by Date:
**Re: Miscellany** - Prev by thread:
**Re: integrals** - Next by thread:
**Re: integrals** - Index(es):