Groups | Search | Server Info | Login | Register

Groups > comp.specification.z > #370

Re: assertions about parts of schema

Newsgroups comp.specification.z
Date 2013-04-03 23:41 -0700
References <kj7g95$vfe$1@dont-email.me> <01418bc9-dcb9-4915-9781-1dfd1c2a6c04@googlegroups.com> <kjfvqi$6qp$1@dont-email.me> <505bd5c0-c9e3-4dab-87bb-bb43ab2d9944@googlegroups.com> <3aa3f63b-cb64-4de2-a9ca-79fbc596d85a@googlegroups.com>
Message-ID <346da566-2ee8-42fe-ae39-e5bb3b32447b@googlegroups.com> (permalink)
Subject Re: assertions about parts of schema
From phil.clayton@lineone.net

Show all headers | View raw

On Wednesday, April 3, 2013 11:34:53 PM UTC+1, phil.c...@lineone.net wrote:
> In fact, thinking some more, one can write the schema {b} in Spivey Z as
> 
> 
> 
>   {Big | θBig = b}

Provided b ∈ Big.  Given this, the benefit of using σ probably goes.

> so, following previous suggestions, I think you could write
> 
>   (\{Big | \theta Big = v1\} \project \sigma Small) = (\{Big | \theta Big = v2\} \project \sigma Small)

To be valid Spivey, I think that should have been:

  ([Big | \theta Big = v1] \project \sigma Small) = ([Big | \theta Big = v2] \project \sigma Small)

Perhaps better still, with no \mu or \project:

  (\{Big | \theta Big = v1 @ \theta Small\}) = (\{Big | \theta Big = v2 @ \theta Small\})

Back to comp.specification.z | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

assertions about parts of schema David Lamb <dalamb@cs.queensu.ca> - 2013-03-30 16:02 -0400
  Re: assertions about parts of schema phil.clayton@lineone.net - 2013-04-02 14:01 -0700
    Re: assertions about parts of schema David Lamb <dalamb@cs.queensu.ca> - 2013-04-02 21:17 -0400
      Re: assertions about parts of schema phil.clayton@lineone.net - 2013-04-03 14:29 -0700
        Re: assertions about parts of schema phil.clayton@lineone.net - 2013-04-03 15:34 -0700
          Re: assertions about parts of schema phil.clayton@lineone.net - 2013-04-03 23:41 -0700
        Re: assertions about parts of schema David Lamb <dalamb@cs.queensu.ca> - 2013-04-04 17:08 -0400
          Re: assertions about parts of schema phil.clayton@lineone.net - 2013-04-04 15:01 -0700
            Re: assertions about parts of schema David Lamb <dalamb@cs.queensu.ca> - 2013-04-04 20:37 -0400

csiph-web