COMMENT ⊗   VALID 00003 PAGES
C REC  PAGE   DESCRIPTION
C00001 00001
C00002 00002	Early 1960s - reported in SIP by Minsky
C00005 00003	Weaknesses:
C00007 ENDMK
C⊗;
Early 1960s - reported in SIP by Minsky

First program to use Analogy (explicitly) 

Task: IQ type A:B :: C:?, where ? one of 5 figures (P 273)

Process:  290-294
 ---- Part 1 ----
  1) Describe all Figures (A-C, 1-5)
	Finds properties, relations of objects in each figure
  2) Find transformations: A→B, C→i ∀i; 
	also A→C, B→C, & A→i, B→i ∀i
	This object-in-1 is like object-in-2, when rotated, scaled, ...
 ---- Part 2 ----
  3) a) Find mapping from A→B, consistent with relations (variabulize)
	[MATCH, ADD, REMOVE objects]
     b) Find mapping from C→i, consistent with relations
  4) Try A→B rule on C; to see if get i.
  5) Iteratively weaken A→B xform (by eliminating conjuncts) 
	until corresponds to unique C→j.
	This is least weak, and j is answer.

Comments:
	General:
  No looping back to description - used seperate modules (IBM cards)
  Form required, but actual relations arbitrary.
	Specific:
  re: 1) - Based on fixed language,
	   Positive properties
	   Really 0th step, for decompostion.
  re: 3) - Non recursive - either equal or not
	   Conjunct of properties
  re: 4) - An optimization:
	3.5) Throw out C→i if #'s don't match.
		If all gone, relax.
  re: 5) - Order heuristic - to correspond to humans
	   If non-unique, try again.
Weaknesses:
  Only conjuncts of positive traits
	[Eg not No object of A is = object of B]
  Unable to recur - objects either EQUAL or not.
  Unable to adapt - ie heuristics used built-into code
	[Eg another order of attempts, how to weaken conjunct]
  Unable to return to decomposing step.
  Limited in scope to discriminary - 
	Able to find best from sample, not "good".
 In summary: totally syntactic - no world knowledge, just other smarts.

Strengths:
  Did work - over large case
  Knew some of these weaknesses - esp 4.
  Arbitrary relations (for part 2, eg shading)
  Some good optimizations

Final comments:
1. This first big LISP program - justifies PLISTs, etc.
2. Granddaddy of most ANALOGY programs
	Worked symbolically.
	Well (objectively) described. 
	  - of problem, future directions and implementation.