|Date:||2016, November 8|
|Title:||Generalised Substitution Systems|
We present the notion of generalised substitution system as introduced by Tutu and Fiadeiro. Generalised substitution systems formalise the notion of logical system in an abstract way, like institutions do. However, generalised substitution systems add an operational aspect, which allows for the easy formalisation of the notions of query, solution and computed answer. There is also a variant of Herbrandís theorem, which shows the interplay between denotational and operational semantics of logic programming. All this is done in a logic-independent way.