[sv-ac] never


Subject: [sv-ac] never
From: John Havlicek (john.havlicek@motorola.com)
Date: Tue Feb 18 2003 - 16:19:09 PST


All:

In the semantics subcommittee, concern has been raised over conflict
between the intuitive meaning of "never" and its intended semantics.

On pp. 63-64 of LRM Rev0.80, there is a somewhat confusing description
of the meaning of "never". This description says, "Effectively, it
[never] negates the property expression", which strongly suggests that
the intended meaning of "never" is property negation.

In the context of linear temporal logic, "never" is typically
understood to mean "always not". Therefore there is the potential
for serious confusion over the meaning of "never", especially in
distinguishing

   initial never s

from

   always never s

Best regards,

John Havlicek



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