Re: On Formal IS-A definition
From: David BL <davidbl_at_iinet.net.au>
Date: Thu, 6 May 2010 16:13:52 -0700 (PDT)
Message-ID: <a096900f-8f56-4c3f-8333-e2e98f270b2d_at_h37g2000pra.googlegroups.com>
Date: Thu, 6 May 2010 16:13:52 -0700 (PDT)
Message-ID: <a096900f-8f56-4c3f-8333-e2e98f270b2d_at_h37g2000pra.googlegroups.com>
On May 6, 9:10 pm, Bob Badour <bbad..._at_pei.sympatico.ca> wrote:
> If one is interested specifically in subtypes of supertypes, a proper
> subset of a type with a proper superset of operations is a proper
> subtype of that type. Thus, circle values are a subtype of ellipse
> values and ellipse variables are a subtype of circle variables.