From: [email-masked]
Date: Fri, 19 Feb 1999 13:47:33 -0500

At 03:31 PM 2/18/99 -0800, Andrea Westerinen wrote:
>This is getting scary.  If you have multiple validity periods that should be
>analyzed together in an ORed combination then you have an implicit DNF
>condition structure....
>
>(period1 OR period2 OR period3 ...) AND (other policyConditions)
>
>So, why don't we just stick with the DNF/CNF structure?  
>

because if (other policyConditions) is DNF, then the complete expression

(period1 OR period2 OR period3 ...) AND (other policyConditions)

is a three level boolean expression of the form:

(period1 OR period2 OR period3 ...) AND ( (A AND B) OR (C AND D) ).

If we stick with DNF/CNF, the conjunction/disjunction of the validity period will also force the conjunction/disjunction in (other policyConditions), e.g.

(period1 OR period2 OR period3 ...) AND ( (A AND B) OR (C AND D) ) is invalid since it is not CNF/DNF, but

(period1 OR period2 OR period3 ...) OR( (A AND B) OR (C AND D) ) is valid since it is DNF.

-- Silvano

Silvano Gai               
Cisco Systems                  Empowering the Internet Generation
170 West Tasman Drive                         Tel. (408) 527 2690
San Jose, CA, 95134-1706                      Fax. (408) 526 2690
                                                   [email-masked]