Semantic Stack Architecture
The traditional Semantic Stack layers Rules and Logic onto core Semantic Web technologies like RDF, RDFS, OWL and SPARQL.
Figure 1 below represents an interpretion of this inspired by Figure 11-2 of "Programming the Semantic Web" by Toby Segaran, Colin Evans and Jamie Taylor, published by O'Reilly 2009, but brought up to date and with the juxtapositioning of Proof, Logic and Rules ammended to match that shown in the Wikipedia article referenced above.
Figure 1. A Practical Interpretion of Current Semantic Stack Technologies
We agree with Toby Segaran, Colin Evans and Jamie Taylor that current implementations of SPARQL and OWL are incomplete and therefore cannot sit wholly within the domain of Practical Semantic Technologies. Some progress has been made with SWRL towards the representation and storage of rules but this is far from wholly practical. The bulk of Rule support, and all of Logic and Proof still persist as Future and Fantasy Technologies to borrow the terminology of the above mentioned authors.
We take a different view of how the stack should be configured, see figure 2 below.
For us the Semantic Web is severely handicapped as a practical technology if its architecture doesn't provide core support for the transparent handling of both explicit (or concrete) and implicit (or generalised) facts better known as rules.
If Semantic Web data and query services are to support Rules and Logic capabilities then these need to exploit underlying inferencing services. For this reason our revised Semantic Stack shown below puts Logic services at the core of all the other traditional Semantic Web technologies. Specifically, we have implemented Higher Order Logic services inorder to support fully generalised triple based logic representations.
Figure 2. Semanticle re-configured Semantic Stack for inbuilt Logic, Rules and Visualisation Pipe based Delivery services
As the above diagram shows this re-configuration of the traditional Semantic Stack promises the potential to radically shift the balance between practical and future fantasy technologies in the crucially important area of the representation, storage and exploitation of rules and logic.