@INCOLLECTION{Basin96a,
AUTHOR        = {David Basin, Sean Matthews and Luca Vigano},
TITLE         = {A Topography of Labelled Modal Logics},
BOOKTITLE     = {Book from Frocos Proceedings},
PUBLISHER     = {Kluwer series on Applied Logic},
VOLUME        = 3, 
EDITOR        = {Franz Baader and Klaus U. Schulz},
YEAR          = {1996},
PAGES         = {75--92},
BIBTYPE       = {INCOLLECTION},
ABSTRACT = {
Labelled Deductive Systems provide a general method for
representing logics in a modular and transparent way.  A Labelled Deductive
System consists of two parts, a base logic and a labelling algebra, which 
interact through a fixed interface.  The labelling 
algebra can be viewed as an independent parameter:  the 
base logic stays fixed for a given class of related logics from which we can
generate the one we want by plugging in the appropriate algebra.  
Our work identifies an important property of the
structured presentation of logics, their combination, and extension.
Namely, there is tension between modularity and extensibility: a narrow
interface between the base logic and labelling algebra can limit the
degree to which we can make use of extensions to the labelling algebra.
We illustrate this in the case of modal logics and apply simple results
from proof theory to give examples.
},
}