 |
 |
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:[log in to unmask]] On Behalf Of Gerard Bricogne > Sent: Friday, May 02, 2014 7:17 PM > To: [log in to unmask] > 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 <[log in to unmask]> 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 [[log in to unmask]] on behalf of >>>> Bernhard Rupp [[log in to unmask]] >>>> Sent: Friday, May 02, 2014 3:04 AM >>>> To: [log in to unmask] >>>> 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 >