Log24

Thursday, August 13, 2015

Anniversary

Filed under: General,Geometry — m759 @ 10:01 am

Today is reportedly the anniversary of the death,
in Paris in 1822, of Jean Robert Argand.

Some related material

From MacTutor

"Wessel's fame as a mathematician rests solely
on this paper, which was published in 1799,
giving for the first time a geometrical interpretation
of complex numbers. Today we call this geometric
interpretation the Argand diagram but Wessel's
work came first. It was rediscovered by Argand 
in 1806 and again by Gauss in 1831. ….

Of course it is not unreasonable to call the
geometrical interpretation of complex numbers
the Argand diagram since it was Argand's work
which was influential. It was so named before
the world of mathematics learnt of Wessel's prior
publication. In fact Wessel's paper was not
noticed by the mathematical community until 1895…."

See also Tilting at Whirligigs (Log24 on March 8, 2008)
and The Galois Quaternion.

Sunday, January 15, 2012

Sunday School

Filed under: General — m759 @ 9:00 am

Identity Crisis— Or, Tilting at Whirligigs 

Sunday, March 9, 2008

Sunday March 9, 2008

Filed under: General — m759 @ 1:00 am

Identity

The 3x3 grid as religious symbol

Click for context.

Related material:

Pictures of Nothing

Art Wars: Epiphany

Tilting at Whirligigs

Down the Up Staircase

Saturday, March 8, 2008

Saturday March 8, 2008

Filed under: General,Geometry — m759 @ 1:00 pm
Tilting at
Whirligigs

From a New York Times list

of literary “signature passages” —

Don Quixote -- 'wasteland and crossroad places'

An answer:

“The whirligig of time”
— Shakespeare, Twelfth Night

and

Log24, Twelfth Night, 2006:

Hamilton’s Whirligigs

Hamilton's Whirligigs: The 8-element quaternion group as a subgroup of the 48-element group GL(2,3)

Click image to enlarge.

Related material:

Rotation in the complex plane.

The plane was discovered
in the late 1700’s by Wessel:

Caspar Wessel

by J.J. O’Connor
 and E.F. Robertson:

“Wessel’s paper [in Danish] was not noticed by the mathematical community until 1895… A French translation… was published in 1897 but an English translation of this most remarkable work was not published until 1999 (exactly 200 years after it was first published)….

We have called Wessel’s work remarkable, and indeed although the credit has gone to Argand, many historians of mathematics feel that Wessel’s contribution was [1]:-

… superior to and more modern in spirit to Argand’s.

In the [1] article the approaches by Argand and Wessel are compared and contrasted. Of course Wessel was a surveyor and his paper was motivated by his surveying and cartography work:-

Wessel’s development proceeded rather directly from geometric problems, through geometric-intuitive reasoning, to an algebraic formula. Argand began with algebraic quantities and sought a geometric representation for them. … Wessel’s initial formulation was remarkably clear, direct, concise and modern. It is regrettable that it was not appreciated for nearly a century and hence did not have the influence it merited.

However more is claimed for Wessel’s single mathematical paper than the first geometric interpretation of complex numbers. In [3] Crowe credits Wessel with being the first person to add vectors. Again this shows the depth of Wessel’s thinking but again, as the paper was unnoticed it had no influence on mathematical development despite appearing in the Memoirs of the Royal Danish Academy which by any standard was a major source of publications….

1. … Biography in Dictionary of Scientific Biography (New York 1970-1990).

3. M.J. Crowe, A History of Vector Analysis (Notre Dame, 1967).”

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