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␈↓ ↓H␈↓␈↓βS␈↓∧ Artificial Intelligence Laboratory, STANFORD UNIVERSITY, Stanford, California 94305

␈↓ ↓H␈↓∧Telephone 415 497-4430␈↓ 
∃March 9, 1978 




␈↓ ↓H␈↓Professor Paul W. Abraham
␈↓ ↓H␈↓Computer Science Department
␈↓ ↓H␈↓Courant Institute of Mathematical Sciences
␈↓ ↓H␈↓251 Mercer Street
␈↓ ↓H␈↓New York, N.Y. 10012

␈↓ ↓H␈↓Dear Paul:

␈↓ ↓H␈↓I␈αdo␈αnot␈αthink␈αthere␈αwas␈αmuch␈αmore␈αresemblance␈αbetween␈αthe␈αearly␈αideas␈αfor␈αLISP␈αand␈αIPL␈αthan
␈↓ ↓H␈↓is discussed in the present drafts of my paper.  At least I couldn't think of any.

␈↓ ↓H␈↓I␈αcalled␈αRoland␈αSilver␈αto␈αask␈αabout␈αhis␈αrelation␈αto␈αthe␈αgarbage␈αcollector␈αand␈αhe␈αsaid␈αthat␈αhe␈αmake
␈↓ ↓H␈↓a␈αcompacting␈αgarbage␈αcollector␈αfor␈αthe␈αLISP␈αhe␈αimplemented␈αon␈αSTRETCH␈αsome␈αyears␈αlater,␈αbut
␈↓ ↓H␈↓that␈αhe␈αhad␈αnot␈αconnected␈αwith␈αthe␈αoriginal␈αgarbage␈αcollector.␈α He␈αreminded␈αme␈αthat␈αI␈αhad␈αasked
␈↓ ↓H␈↓him the same question a year previously.

␈↓ ↓H␈↓I will say more about M-expressions.

␈↓ ↓H␈↓I␈α⊂still␈α⊃do␈α⊂not␈α⊃remember␈α⊂any␈α⊃competition␈α⊂with␈α⊂Doug␈α⊃Ross's␈α⊂group␈α⊃in␈α⊂programming␈α⊃the␈α⊂Wang
␈↓ ↓H␈↓algorithm.

␈↓ ↓H␈↓Finally,␈α
not␈α
enough␈α
happened␈α
with␈αthe␈α
advice␈α
taker␈α
at␈α
that␈αtime␈α
to␈α
justify␈α
saying␈α
more␈α
about␈αit
␈↓ ↓H␈↓than the paper already does.

␈↓ ↓H␈↓Thanks again for writing.


␈↓ ↓H␈↓Best regards,



␈↓ ↓H␈↓John McCarthy
␈↓ ↓H␈↓Director
␈↓ ↓H␈↓Professor of Computer Science

␈↓ ↓H␈↓cc:  Jean Sammet, Carl Hewitt