Bourbaki dangerous bend symbol: Difference between revisions
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[[File:Dangerous bend symbol.png|thumb|left|Knuth's "Dangerous Bend" sign]] |
[[File:Dangerous bend symbol.png|thumb|left|Knuth's "Dangerous Bend" sign]] |
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The '''dangerous bend''' symbol ☡ ([[unicode]] number x02621) was created by the [[Nicolas Bourbaki]] group of mathematicians and appears in the margins of [[mathematics]] books written by the group. It resembles a [[Traffic sign|road sign]] that indicates a "dangerous bend" in the road ahead, and is used to mark passages tricky on a first reading or with an especially difficult argument.<ref>Steven G. Krantz (2011), ''[http://books.google.com/books?id=mMZBtxVZiQoC&pg=PA92 The Proof Is in the Pudding: The Changing Nature of Mathematical Proof]'', Springer, ISBN 0387489088, p. 92.</ref> |
The '''dangerous bend''' or '''caution'' symbol ☡ ([[unicode]] number x02621) was created by the [[Nicolas Bourbaki]] group of mathematicians and appears in the margins of [[mathematics]] books written by the group. It resembles a [[Traffic sign|road sign]] that indicates a "dangerous bend" in the road ahead, and is used to mark passages tricky on a first reading or with an especially difficult argument.<ref>Steven G. Krantz (2011), ''[http://books.google.com/books?id=mMZBtxVZiQoC&pg=PA92 The Proof Is in the Pudding: The Changing Nature of Mathematical Proof]'', Springer, ISBN 0387489088, p. 92.</ref> |
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Others have used variations of the symbol in their textbooks, and computer scientist [[Donald Knuth]] introduced a more realistic road-sign depiction in his [[Metafont]] and [[TeX]] systems.<ref>Donald Ervin Knuth (1984), ''[http://books.google.com/books?id=hEYuAQAAIAAJ The TeXbook]'', Addison-Wesley, ISBN 0201134489.</ref><ref>Donald Ervin Knuth (1986), ''[http://books.google.com/books?id=GghUAAAAMAAJ The METAFONTbook]'', Addison-Wesley, ISBN 0201134454.</ref> |
Others have used variations of the symbol in their textbooks, and computer scientist [[Donald Knuth]] introduced a more realistic road-sign depiction in his [[Metafont]] and [[TeX]] systems.<ref>Donald Ervin Knuth (1984), ''[http://books.google.com/books?id=hEYuAQAAIAAJ The TeXbook]'', Addison-Wesley, ISBN 0201134489.</ref><ref>Donald Ervin Knuth (1986), ''[http://books.google.com/books?id=GghUAAAAMAAJ The METAFONTbook]'', Addison-Wesley, ISBN 0201134454.</ref> |
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Revision as of 12:08, 4 September 2011
Certains passages sont destinés à prémunir le lecteur contre des erreurs graves, où il risquerait de tomber; ces passages sont signalés en marge par le signe ☡ («tournant dangereux»)
Some passages are designed to guard the reader against serious errors, where he risks falling; these passages are signposted in the margin by the sign ☡ ("dangerous bend")
— Nicholas Bourbaki's description of the symbol in several textbooks[1]
The dangerous bend' or caution symbol ☡ (unicode number x02621) was created by the Nicolas Bourbaki group of mathematicians and appears in the margins of mathematics books written by the group. It resembles a road sign that indicates a "dangerous bend" in the road ahead, and is used to mark passages tricky on a first reading or with an especially difficult argument.[2]
Others have used variations of the symbol in their textbooks, and computer scientist Donald Knuth introduced a more realistic road-sign depiction in his Metafont and TeX systems.[3][4]
Typography
In the LaTeX typesetting system (version 3), the dangerous bend symbol can be written as:[5]
\begin{danger} ... \end{danger}
\begin{ddanger} ... \end{ddanger}.
References
- ^ See, for example, Théorie des ensembles, p. I-8.
- ^ Steven G. Krantz (2011), The Proof Is in the Pudding: The Changing Nature of Mathematical Proof, Springer, ISBN 0387489088, p. 92.
- ^ Donald Ervin Knuth (1984), The TeXbook, Addison-Wesley, ISBN 0201134489.
- ^ Donald Ervin Knuth (1986), The METAFONTbook, Addison-Wesley, ISBN 0201134454.
- ^ Frank Mittelbach, Michel Goossens, Johannes Braams, David Carlisle, Chris Rowley, Christine Detig, and Joachim Schrod (2004), The LaTeX Companion, Chapter 3: Basic Formatting Tools, Addison-Wesley.