From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Contracts in generic formal subprogram
Date: Thu, 13 Apr 2023 08:27:30 +0200 [thread overview]
Message-ID: <u187ci$9mpm$1@dont-email.me> (raw)
In-Reply-To: <wTNwzuVC4pvpqJ=Iw@bongo-ra.co>
On 2023-04-12 04:18, Spiros Bousbouras wrote:
> On Tue, 11 Apr 2023 14:03:27 +0200
> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote:
>> The formal meaning of weaker/stronger relation on predicates P and Q:
>>
>> weaker P => Q
>> stronger Q => P
>>
>> The formal rationale is that if you have a proof
>>
>> P1 => P2 => P3
>>
>> Then weakening P1 to P1' => P1 and strengthening P3 => P3' keeps it:
>>
>> P1' => P2 => P3'
>
> You have it backwards ; if P1' implies P1 then P1' is stronger
> than P1 .
Yes, you are right. Inclusion is an inverse of implication.
A weaker predicate is true on a set that contains the set where the
stronger predicate is.
--
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
next prev parent reply other threads:[~2023-04-13 6:27 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-08 7:00 Contracts in generic formal subprogram mockturtle
2023-04-08 8:02 ` Dmitry A. Kazakov
2023-04-11 5:56 ` G.B.
2023-04-11 12:03 ` Dmitry A. Kazakov
2023-04-12 2:18 ` Spiros Bousbouras
2023-04-12 3:37 ` Spiros Bousbouras
2023-04-12 6:49 ` Niklas Holsti
2023-04-12 7:30 ` G.B.
2023-04-12 12:29 ` Ben Bacarisse
2023-04-13 6:27 ` Dmitry A. Kazakov [this message]
2023-04-08 9:09 ` Randy Brukardt
2023-04-08 16:48 ` Simon Wright
2023-04-08 17:27 ` mockturtle
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