* (next-nodes 'c +graph1+)

(B D)

* (next-nodes-set '(c) +graph1+)

(B D)

* (next-nodes-set '(a c) +graph1+)

(C B D)

* (next-nodes-set '(g) +graph1+)

NIL

* (next-nodes-set nil +graph1+)

NIL

* (exactly-reachable-nodes 'a +graph1+ 0)

(A)

* (exactly-reachable-nodes 'a +graph1+ 3)

(D C E)

* (exactly-reachable-nodes 'e +graph1+ 3)

NIL

* (mapcar #'(lambda (x) (exactly-reachable-nodes x +graph1+ 3)) '(a b c d e f g h))

((D C E) (D B F) (D B C E F) (D C E G) NIL NIL NIL NIL)

* (exactly-reachablep 'a 'b +graph1+ 3)

NIL

* (exactly-reachablep 'a 'd +graph1+ 3)

T