Bernhard is giving me too much credit. I just told him I'd seen someone's name
associated with the 65 space groups, but that's the only information I
provided. Ron
On Fri, 2 May 2014, Bernhard Rupp wrote:
Fellows,
my apologies for having sparked that space war.
I wish to interject than in my earlier postings to this thread
to Howard I did give credit to the '65 sons of Sohnke' (albeit sans c).
If we honor him, we ought to spell him right.
http://reference.iucr.org/dictionary/Sohnke_groups
Sohnke (IUCr)
Sohncke (same page, IUCr)
Sohncke (Wikipedia and German primary sources):
http://www.deutsche-biographie.de/sfz80497.html
Ron posted the Sohncke link to me off-line right away and I admit that I
realized the same by googling
'chiral space groups' which immediately leads you to Wikipedia's space group
and Sohncke
entry. It also shows (in addition to an interesting 74-group page...) my own
web list, which imho
erroneously used the improper (no pun intended) adjective 'chiral' for the 65
Sohncke groups. No more.
Nonetheless, this does not necessarily discredit my quest for a descriptive
adjective, and the
absence of such after this lively engagement might indicate that the question
was not quite as
illegitimate as it might have appeared even to the cognoscenti at first sight.
Nonetheless,
a toast to Sohncke!
BR
-----Original Message-----
From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Gerard
Bricogne
Sent: Friday, May 02, 2014 7:17 PM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Confusion about space group nomenclature
Dear John,
What is wrong with honouring Sohnke by using his name for something that he
first saw a point in defining, and in investigating the properties resulting
from that definition? Why insist that we should instead replace his name by an
adjective or a circumlocution? What would we say if someone outside our field
asked us not to talk about a Bragg reflection, or the Ewald sphere, or the Laue
method, but to use instead some clever adjective or a noun-phrase as long as
the name of a Welsh village to explain what these mean?
Again, I think we should have a bit more respect here. When there are simple
adjectives to describe a mathematical properties, the mathematical vocabulary uses it
(like a "normal" subgroup). However, when someone has seen that a definition by
a conjunction of properties (i.e. something describable by a sentence) turns out to
characterise objects that have much more interesting properties than just those by which
they were defined, then they are often called by the name of the mathematician who first
saw that there is more to them than what defines them. Examples: Coxeter groups, or Lie
algebras, or the Leech lattice, or the Galois group of a field, the Cayley tree of a
group ... . It is the name of the first witness to a mathematical phenomenon, just as we
call chemical reactions by the name of the chemist who saw that mixing certain chemicals
together led not just to a mixture of those chemicals.
So why don't we give Sohnke what belongs to him, just as we expect other
scientists to give to Laue, Bragg and Ewald what we think belongs to them?
Maybe students would not be as refractory to the idea as might first be thought.
With best wishes,
Gerard.
--
On Fri, May 02, 2014 at 05:42:34PM +0100, Jrh Gmail wrote:
Dear George
My student class would not find that IUCr dictionary definition helpful. What
they do find helpful is to state that they cannot contain an inversion or a
mirror.
To honour Sohnke is one thing but is it really necessary as a label? You're
from Huddersfield I am from Wakefield ie let's call a spade a spade (not a
'Black and Decker').
Cheers
John
Prof John R Helliwell DSc
On 2 May 2014, at 17:01, George Sheldrick <gshe...@shelx.uni-ac.gwdg.de> wrote:
In my program documentation I usually call these 65 the Sohnke space groups, as
defined by the IUCr:
http://reference.iucr.org/dictionary/Sohnke_groups
George
On 05/02/2014 02:35 PM, Jim Pflugrath wrote:
After all this discussion, I think that Bernhard can now lay the claim that these 65
space groups should really just be labelled the "Rupp" space groups. At least
it is one word.
Jim
From: CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] on behalf of
Bernhard Rupp [hofkristall...@gmail.com]
Sent: Friday, May 02, 2014 3:04 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Confusion about space group nomenclature .
Enough of this thread.
Over and out, BR
--
Prof. George M. Sheldrick FRS
Dept. Structural Chemistry,
University of Goettingen,
Tammannstr. 4,
D37077 Goettingen, Germany
Tel. +49-551-39-33021 or -33068
Fax. +49-551-39-22582
