COMMENT ⊗   VALID 00002 PAGES
C REC  PAGE   DESCRIPTION
C00001 00001
C00002 00002	.CENT(Problems)
C00005 ENDMK
C⊗;
.CENT(Problems)
.BEGIN TABIT1(10);
I Which of the following are dotted-pairs?
\%21.%3 (X . Y)   %22.%3 ((A .(B . C))  %23.%3  A2   %24.%3 (X . Y2 . Z)
.GROUP SKIP 2;
%1
II Write the following as LISP trees:
\%21.%3  ((A . B).(B . (C . D)))  %22.%3  (((A . B).C).E)

\%23.%3  ((X . NIL).(Y .(Z . NIL)))    %24.%3  (NIL . NIL)
.GROUP SKIP 2;
%1
.GROUP
III Write the following LISP trees as S-exprs:


.BEGIN SELECT g;NOFILL;PREFACE 0 MILLS;GROUP;
.TURN OFF "%","#","\";
.TURN ON "∞" FOR "%";
.TURN ON "?" FOR "\";
.TABS 20,40;
          ∞21.∞*  ? ∞22.∞*	? ∞23.∞*
	    /\    ?   /\        ?    /\
	   /  \   ?  /  \	?   /  \
	  /   /\  ? ∞3A∞*   /\	?  ∞3A∞*   /\
	 /   /  \ ?    /  \	?     /  \
	∞3A∞*   ∞3B∞*    ∞3C∞*?   /    \	?    ∞3B∞*   /\
		  ?  /\    /\	?       /  \
		  ? /  \   ∞3D∞* ∞3E∞*	?      ∞3C∞*   /\
		  ? ∞3A∞*  ∞3NIL∞*	?         /  \
		  ?		?        ∞3D∞*   ∞3NIL∞*
.END



.APART
.GROUP
.BEGIN SELECT b;NOFILL;PREFACE 0 MILLS;GROUP;
.TURN OFF "%","#","α";
.TURN ON "∞" FOR "%";

⊂αααααπααα⊃  ⊂αααπααααα⊃        ⊂ααααααπααα⊃  ⊂αααπααα⊃  ⊂αααπααααα⊃
~  #  ~ #αβα→~ # ~  #  ~	~ CONS ~ #αβα→~ X ~ #αβα→~ Y ~ NIL ~
%ααβαα∀ααα$  %αβα∀ααβαα$	%αααααα∀ααα$  %ααα∀ααα$  %ααα∀ααααα$
   ↓           ~    ↓
  CAR          ~   NIL
               ~  ⊂αααααπααα⊃  ⊂αααπααααα⊃
	       %α→~  #  ~ #αβα→~ # ~  #  ~
		  %ααβαα∀ααα$  %αβα∀ααβαα$
		     ↓           ↓    ↓
		   QUOTE         A   NIL
.END
.APART
.END