1. Assignment 1: Preparing Zed-Specification Document
Brief:
You will take your project concept a step further by developing its zed specification.
It is crucial to realise that in a Z specification, the mathematics is subsidiary to the
natural language. A piece of mathematics makes no sense unless we know the in-
tended meaning of each construct. We therefore enforce a rule that an "English de-
scription must precede the corresponding Z" (by Anthony Hall). The English and the
Z are complementa-ry: the English describes the relevant real-world concept and
explains the meaning of every term in the maths; the maths makes precise the
relationships between the terms defined in the English.
A Z Tool for Specification:
Industry uses Microsoft Word for writing specifications so the prescribed tool for
writing Zed specification in word is "Z Word Tool" developed by Anthony Hall,
and his colleagues.
The tool includes:
1.Styles for laying out schemas and other Z paragraphs.
2.A Unicode font that includes all the Z symbols and is visually compatible with
Times New Roman.
3.Automatic layout of Z paragraphs.
Pattern for the Document:
Every schema that defines part of the system state is preceded by an explanation of
what properties of the real world are being described. Here is a small example:
Attribute Name Description
Known Known is the set of names.
Birthday Birthday is a function when applied to certain names gives the
birthdays associated to them.
Invariant Set known is same as the domain of the function birthday
BirthdayBook
Known: ℙ Name
Birthday: Name ⇸ Date
Known = dom birthay
So,
1. Create hierarchy of your selected project. Identify any of the three modules for
formal specification document.
2. Create State Schema of your selected project and write down English
description of real world properties.
3. Also give initSchema for state schema.
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2. 4. Now apply operations on state schema and state them as operation schema.
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