Tossing a Coin

In Section 4.2.3 we described a plan for ending up with a flat coin. The decision in this plan does not distinguish between the coin landing heads-up and tails-up---the decision rules are ambiguous.

Initial:       (HOLDING-COIN)

Step  1 (2): (TOSS-COIN)
               (AND (NOT (HOLDING-COIN)) (ON-TABLE))
                  0 -> (HOLDING-COIN)

Step  2 (4): (INSPECT-COIN)
               (AND (KNOW-IF (FLAT-COIN)) (KNOW-IF (HEADS-UP))
                (KNOW-IF (TAILS-UP)) (KNOW-IF (ON-EDGE)))

Step  3 (3): (DECIDE UNK2S)
               (and (FLAT-COIN)
                    T                ) => [UNK2S: H]
               (and (FLAT-COIN)
                    T                ) => [UNK2S: T]
               (and (ON-EDGE)
                    T                ) => [UNK2S: E]
                  2 -> (KNOW-IF (FLAT-COIN))
                  2 -> (KNOW-IF (ON-EDGE))

Step  4 (1): (TIP-COIN)                           YES: [UNK2S: E]
                                                  NO : [UNK2S: H T]
               (FLAT-COIN)
                  1 -> (ON-EDGE)                  NO : [UNK2S: H T]

Goal:        (FLAT-COIN)

             GOAL                                 YES: [UNK2S: T]
                  1 -> (FLAT-COIN)                NO : [UNK2S: H E]

             GOAL                                 YES: [UNK2S: H]
                  1 -> (FLAT-COIN)                NO : [UNK2S: T E]

             GOAL                                 YES: [UNK2S: E]
                  4 -> (FLAT-COIN)                NO : [UNK2S: H T]

Complete!