The Math Forum



Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.


Math Forum » Discussions » Inactive » Historia-Matematica

Topic: [HM] Name needed for a point: Hirst?
Replies: 4   Last Post: Jan 10, 2000 3:57 AM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Julio Gonzalez Cabillon

Posts: 1,353
Registered: 12/3/04
Re: [HM] Name needed for a point: Hirst?
Posted: Jan 7, 2000 11:09 PM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply


Gunter Weiss <weiss@math.tu-dresden.de> wrote:

> From what I read and learned I got the impression, that Hirst
> simply generalised the classical 'inversion': Given a center
> C and a (regular or singular) polarity \pi in a projective
> space, then the (C,\pi)-inverse X' to a point X (not= C) is
> defined by
> (HI-1) C, X, X' are collinear,
> (HI-2) X, X' are \pi-conjugate.
>
> One will call X' the Hirst inverse to X with respect to the
> inversion center C and the polarity \pi.


This transformation has been referred to as "conic inversion". Giusto
Bellavitis (1803-1880) seems to have been the first to study it as
early as 1838. I seem to recall that Franz Seydewitz (1807-1852) was
also interested in this transformation (but not earlier than 1840). I
may look some pointers up, if necessary. Thomas Archer Hirst (1830-1892)
came later (c. 1865). By the way, there is a curious six-part series
on Hirst's life published in the Monthly (1993). And, just for the
record, let me point out that the MacTutor History of Mathematics
Archive (St Andrews, Scotland) at
http://www-history.mcs.st-and.ac.uk/history/Mathematicians/Hirst.html
has Hirst's death-date wrong -- in fact, TAH died on February 16, 1892.

Julio Gonzalez Cabillon






Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© The Math Forum at NCTM 1994-2017. All Rights Reserved.