Thank you for sending me Jim Laurence's answer to the problem I posed to you in my letter of 3/31/75 (copy enclosed.)
Hardly anything bearing exactly on this question has been published: the 2 enclosed reprints may say something of the background
The molecular structures that CONGEN builds ignore stereoisomers (for the present): i.e., they classify the C atom as S4.
At one time I wanted to categorize some stereoisomers. Instead of re-writing the basic program, I thought I would substitute
an A4 graph in place of C; the program would then calculate the appropriate symmetries, albeit at some cost in computational
Hence the question: what is the smallest A4.
You should note that Ray Carhart had already produced a 2l-node graph, and I thought I had sent that to you. We did not know
whether this was the smallest With slings ([diagram]) and higher values we also find one at 22 nodes;
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Lawrence-Klee A4 (nonplanar) graph
[stamped, Mar 18 1976]
how about putting it in Congen to prove it is A4 (and verify the program again)