WEBVTT

1
00:00:00.000 --> 00:00:08.467
This overview explains how a proved Boolean rewrite can preserve
policy decisions while changing the work needed to compute them.

2
00:00:08.467 --> 00:00:15.965
Finding a match, admitting its proof, updating identities,
and handling fallback can cost more than the rewrite saves.

3
00:00:15.965 --> 00:00:15.967
Finding a match, admitting its proof, updating identities,
and handling fallback can cost more than the rewrite saves.

4
00:00:16.267 --> 00:00:19.200
Both routes require authorized staff.

5
00:00:19.200 --> 00:00:24.600
One route accepts allowed hours; the other accepts an explicit exception.

6
00:00:24.600 --> 00:00:30.467
The two branches therefore share A, while B and C are alternatives.

7
00:00:30.467 --> 00:00:34.233
Factor the common staff condition outside the or.

8
00:00:34.233 --> 00:00:38.200
When A is zero, both forms deny access.

9
00:00:38.200 --> 00:00:42.200
When A is one, both forms return B or C.

10
00:00:42.200 --> 00:00:47.900
These two cases prove the equality for every combination of the other conditions.

11
00:00:47.900 --> 00:00:52.967
For authorized staff outside normal hours with an exception, the original branches return

12
00:00:52.967 --> 00:00:54.500
zero and one.

13
00:00:54.500 --> 00:00:56.900
Their or allows access.

14
00:00:56.900 --> 00:01:01.300
The factored form first finds B or C true, then combines it with A one

15
00:01:01.300 --> 00:01:04.766
and also allows access.

16
00:01:04.766 --> 00:01:04.767
and also allows access.

17
00:01:04.767 --> 00:01:10.300
A proved Boolean identity can preserve decisions while reducing structure.

18
00:01:10.300 --> 00:01:17.633
Profitability also includes finding the match, admitting
the proof, updating identities and handling fallback.

19
00:01:17.633 --> 00:01:21.633
Use allow equals role AND region, OR role AND resource.

20
00:01:21.633 --> 00:01:25.667
Factor it to role AND the OR of region and resource.

21
00:01:25.667 --> 00:01:31.200
Exhaustive evaluation over the three inputs confirms equality.

22
00:01:31.200 --> 00:01:35.500
In the revision example, the resource clause changes.

23
00:01:35.500 --> 00:01:39.500
The matching record and proof instance depend on that clause.

24
00:01:39.500 --> 00:01:47.533
They require invalidation or revalidation; an old
cache name alone cannot establish validity.

25
00:01:47.533 --> 00:01:52.033
The factorization is a conceptual proof example.

26
00:01:52.033 --> 00:01:57.467
It is not asserted to be a deployed rule or a measured D-series winner.

27
00:01:57.467 --> 00:02:03.867
A smaller expression can still lose whole-task
time after matching and cache overhead.

28
00:02:03.867 --> 00:02:08.800
Preserve an exact no-rewrite path when advice is rejected.

29
00:02:09.100 --> 00:02:14.433
Work a second complete case with A 0, B 1, C 1.

30
00:02:14.433 --> 00:02:18.100
Keep this assignment fixed throughout the calculation.

31
00:02:18.100 --> 00:02:22.633
Each symbol retains the meaning already introduced; a new value does not

32
00:02:22.633 --> 00:02:25.833
create a new logical rule.

33
00:02:25.833 --> 00:02:28.967
Although both alternative conditions are true, the shared

34
00:02:28.967 --> 00:02:31.800
authorized-staff condition is false.

35
00:02:31.800 --> 00:02:37.133
Both original branches contain that false requirement and return zero.

36
00:02:37.133 --> 00:02:42.733
The factored form keeps A outside the or and also returns zero.

37
00:02:42.733 --> 00:02:46.733
Factoring has preserved the permission boundary.

38
00:02:46.733 --> 00:02:50.033
This case establishes a specific contrast.

39
00:02:50.033 --> 00:02:53.100
A remains required in both forms.

40
00:02:53.100 --> 00:02:57.100
Do not replace the policy with B OR C alone.

41
00:02:57.100 --> 00:03:01.300
Keep the input, intermediate values, and conclusion together when comparing

42
00:03:01.300 --> 00:03:03.367
it with the previous case.

43
00:03:03.367 --> 00:03:09.567
The calculated answer belongs to this complete assignment under the stated rule.

44
00:03:09.867 --> 00:03:14.400
Suppose the exception route now requires D rather than A.

45
00:03:14.400 --> 00:03:19.433
The earlier factorization does not automatically apply, because the two branches no longer

46
00:03:19.433 --> 00:03:21.967
share the same required condition.

47
00:03:21.967 --> 00:03:25.800
The meaning of the revised clause matters.

48
00:03:25.800 --> 00:03:32.033
With A zero, B zero, C one, and D one, the revised policy allows access

49
00:03:32.033 --> 00:03:33.967
through the second branch.

50
00:03:33.967 --> 00:03:39.100
The old factored expression returns zero because it still requires A.

51
00:03:39.100 --> 00:03:46.033
This single complete assignment disproves that proposed rewrite of the revised policy.

52
00:03:46.033 --> 00:03:49.667
Apply exact checking to the current rule version.

53
00:03:49.667 --> 00:03:54.833
After correctness is established, count or measure the work of recognizing, preparing, and

54
00:03:54.833 --> 00:03:56.933
executing the rewrite.

55
00:03:56.933 --> 00:04:01.400
A safe transformation can still cost more than evaluating the original

56
00:04:01.400 --> 00:04:05.600
policy for the requested lifetime.

57
00:04:05.600 --> 00:04:05.608
Check correctness independently of profitability.

58
00:04:05.608 --> 00:04:09.500
Check correctness independently of profitability.

59
00:04:09.500 --> 00:04:15.433
Charge the complete request and retain an exact no-rewrite fallback.
