COMMENT ⊗   VALID 00002 PAGES
C REC  PAGE   DESCRIPTION
C00001 00001
C00002 00002	
C00007 ENDMK
C⊗;


(DEFPROP SAMEF (NIL SAMEFRINGE SAME) VALUE) 

(DEFUN SAMEFRINGE (X Y) 
       (OR (AND (NOT (ATOM X))
		(NOT (ATOM Y))
		(SAME (CAR X) (CAR Y) (CDR X) (CDR Y)))
	   (EQ X Y))) 

(DEFUN SAME (X Y U V) 
       (OR (AND (NOT (ATOM X))
		(NOT (ATOM Y))
		(SAME (CAR X)
		      (CAR Y)
		      (CONS (CDR X) U)
		      (CONS (CDR Y) V)))
	   (AND (NOT (ATOM Y)) (SAME X (CAR Y) U (CONS (CDR Y) V)))
	   (AND (NOT (ATOM X)) (SAME (CAR X) Y (CONS (CDR X) U) V))
	   (AND (EQ X Y) (SAMEFRINGE U V)))) 

(DEFUN SAMEFRINGE1 (X Y) 
       (OR (EQ X Y)
	   (AND (NOT (ATOM X))
		(NOT (ATOM Y))
		(SAME1 (CAR X) (CAR Y) (CDR X) (CDR Y))))) 

(DEFUN SAME1 (X Y U V) 
       (COND ((ATOM X)
	      (COND ((ATOM Y) (AND (EQ X Y) (SAMEFRINGE1 U V)))
		    (T (SAME1 X (CAR Y) U (CONS (CDR Y) V)))))
	     ((ATOM Y) (SAME1 (CAR X) Y (CONS (CDR X) U) V))
	     (T (SAME1 (CAR X)
		       (CAR Y)
		       (CONS (CDR X) U)
		       (CONS (CDR Y) V))))) 

(DEFUN SAMEFRINGE2 (X Y) (SAME2 (ABOT (LIST X)) (ABOT (LIST Y)))) 

(DEFUN SAME2 (U V) 
       (OR (AND (NULL U) (NULL V))
	   (AND (NOT (NULL U))
		(NOT (NULL V))
		(EQ (CAR U) (CAR V))
		(SAME2 (NEXT U) (NEXT V))))) 

(DEFUN NEXT (U) 
       (COND ((NULL U) NIL)
	     ((EQ (CADR U) 'A)
	      (ABOT (CONS (CDADDR U) (CONS 'D (CDDR U)))))
	     (T (NEXT (CDDR U))))) 

(DEFUN ABOT (U) 
       (COND ((ATOM (CAR U)) U)
	     (T (ABOT (CONS (CAAR U) (CONS 'A U)))))) 

(DEFUN SAMEFRINGE3 (X Y) 
       (OR (EQ X Y)
	   (AND (NOT (ATOM X))
		(NOT (ATOM Y))
		((LAMBDA (U V) (AND (EQ (CAR U) (CAR V))
				    (SAMEFRINGE3 (CDR U) (CDR V))))
		 (GOPHER X)
		 (GOPHER Y))))) 

(DEFUN GOPHER (U) 
       (COND ((ATOM (CAR U)) U)
	     (T (GOPHER (CONS (CAAR U) (CONS (CDAR U) (CDR U))))))) 


(DEFUN SAMEFRINGE4 (X Y) 
       (OR (EQ X Y)
	   (AND (NOT (ATOM X))
		(NOT (ATOM Y))
		(SAME4 (GOPHER X) (GOPHER Y)))))
 

(DEFUN SAME4 (X Y) 
       (AND (EQ (CAR X) (CAR Y))
	    (SAMEFRINGE4 (CDR X) (CDR Y))))