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Directory:Jon Awbrey/Papers/Inquiry Driven Systems : Part 6 (view source)
Revision as of 15:00, 15 April 2013
, 15:00, 15 April 2013→6.37. Propositional Types
In any case, the intended term can always be written out in full, as <math>X_j - S.\!</math>
In any case, the intended term can always be written out in full, as <math>X_j - S.\!</math>
<br>
<center>'''Fragments'''</center>
Consider a relation <math>L\!</math> of the following type.
{| align="center" cellspacing="8" width="90%"
| <math>L : \texttt{(} S \texttt{(} T \texttt{))}\!</math>
|}
Consider a relation <math>L\!</math> of the following type.
Consider a relation <math>L\!</math> of the following type.
|}
|}
'''…'''
[The following piece occurs in § 6.35]
The set of triples of dyadic relations, with pairwise cartesian products chosen in a pre-arranged order from a triple of three sets <math>(X, Y, Z),\!</math> is called the ''dyadic explosion'' of <math>X \times Y \times Z.\!</math> This object is denoted <math>\operatorname{Explo}(X, Y, Z ~|~ 2),\!</math> read as the ''explosion of <math>X \times Y \times Z\!</math> by twos'', or more simply as <math>X, Y, Z ~\operatorname{choose}~ 2,\!</math> and defined as follows:
{| align="center" cellspacing="8" width="90%"
| <math>\operatorname{Explo}(X, Y, Z ~|~ 2) ~=~ \operatorname{Pow}(X \times Y) \times \operatorname{Pow}(X \times Z) \times \operatorname{Pow}(Y \times Z).\!</math>
|}
This domain is defined well enough to serve the immediate purposes of this section, but later it will become necessary to examine its construction more closely.
[Maybe the following piece belongs there, too.]
Just to provide a hint of what's at stake, consider the following suggestive identity:
{| align="center" cellspacing="8" width="90%"
| <math>2^{XY} \times 2^{XZ} \times 2^{YZ} ~=~ 2^{(XY + XY + YZ)},\!</math>
|}
What sense would have to be found for the sums on the right in order to interpret this equation as a set theoretic isomorphism? Answering this question requires the concept of a ''co-product'', roughly speaking, a “disjointed union” of sets. By the time this discussion has detailed the forms of indexing necessary to maintain these constructions, it should have become patently obvious that the forms of analysis and synthesis that are called on to achieve the putative reductions to and reconstructions from dyadic relations in actual fact never really leave the realm of genuinely triadic relations, but merely reshuffle its contents in various convenient fashions.
===6.38. Considering the Source===
===6.38. Considering the Source===