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I'm trying to express a given requirement in a software system. I'm used to UML and UseCase specification, but I thought I would attempt to learn Zed Specification (which is based off logic, set theory., etc... so those topics too!)

Given two sets of data

e.g. in Zed notation

[X] ::= a|b|c|d

[Y]::= 1|2|3|4

or in Set Theory

X = {a,b,c,d}

Y = {1,2,3,4}

In set notation I am having difficulty trying to write down the formula for specifying a set containing a list of pairs made from X and Y. Note: Not a Cartesian Product.

So I'm looking for a Set definition for something like this:

MysterySet = {(a,1),(b,2),(c,3),(d,4)}

or a further example,

Material = {(chair,wood),(table,metal),(cup,clay)}

This is basically an analogy for a key-value pair.

Thanks very much.

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# Set of paired elements

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