equal
deleted
inserted
replaced
1448 If started with standard tape @{term "([], [Oc])"}, it halts with the |
1448 If started with standard tape @{term "([], [Oc])"}, it halts with the |
1449 non-standard tape @{term "([Oc], [])"} according to the definition in Chapter 3---so no |
1449 non-standard tape @{term "([Oc], [])"} according to the definition in Chapter 3---so no |
1450 result is calculated; but with the standard tape @{term "([], [Oc])"} according to the |
1450 result is calculated; but with the standard tape @{term "([], [Oc])"} according to the |
1451 definition in Chapter 8. We solve this inconsitency in our formalisation by |
1451 definition in Chapter 8. We solve this inconsitency in our formalisation by |
1452 setting up our definitions so that the @{text counter_example} Turing machine does not |
1452 setting up our definitions so that the @{text counter_example} Turing machine does not |
1453 produce any result, but loops forever fetching @{term Nop}s in state @{text 0}. |
1453 produce any result by looping forever fetching @{term Nop}s in state @{text 0}. |
1454 |
1454 This solution is different from the definition in Chapter 3, but also |
|
1455 different from the one in Chapter 8, where the instruction from state @{text 1} is |
|
1456 fetched. |
1455 *} |
1457 *} |
1456 |
1458 |
1457 (* |
1459 (* |
1458 section {* XYZ *} |
1460 section {* XYZ *} |
1459 |
1461 |