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Showing posts from 2015

How to implement transactions for a triple store in Prolog

For the current research project I'm working on, we're using and RDF triple-store and need to be able to store a large numbers of triples, and assure that after any update a number of constraints are satisfied on the structure of the triples according to our ontology.

In order to implement inserts, updates and deletes, they need to be packaged up inside of a transaction that only commits if the constraints are satisfied in the final image of the triple store.  This means we need a way to do a post-condition driven transaction.

One easy way to implement this is to simply copy the entire database, run the insert/update/delete statements and see if we satisfy the transaction.  If we are changing enormous numbers of triples, it might indeed be the fastest and most reasonable approach.   If we are only changing one triple however, this seems a totally mad procedure.

There is another approach and I'll describe it as follows.

Let's assume that our constraint predicate '…

Judgemental Equality, Homotopy Type Theory and Supercompilation

Ok, time for some incredibly preliminary thoughts on judgemental equality and what it means for Supercompilation and what supercompilation in turn means for judgemental equality.

The more that I explore equality the more incredibly strange the role it plays in type theory seems to be.  There seems intuitively to be nothing more simple than imagining two things to be identical, and yet it seems to be an endless source of complexity.

This story starts with my dissertation, but I'm going to start at the end and work backwards towards the beginning.  Currently I've been reading Homotopy Type Theory, now of some niche fame.  I put off reading about it for a long time because I generally don't like getting too bogged down in foundational principles or very abstract connections with other branches of mathematics (except perhaps on Sundays).  Being more of an engineer than a mathematician, I like my types to work for me, and dislike it when I do too much work for them.

However, …