| Titel |
Context-free languages, coalgebraically |
| Gepubliceerd in |
Software Engineering [SEN], No. SEN-1101. ISSN 1386-369x. |
| Auteur |
Winter, J.; Bonsangue, M.M.; Rutten, J.J.M.M. |
| Datum |
2011-03-01 |
| Trefwoord(en) |
Coalgebra, context-free grammars, context-free languages |
| Taal |
Engels |
| Type |
rapport |
| Uitgever |
CWI |
| Samenvatting |
We give a coalgebraic account of context-free languages using the
functor ${\cal D}(X) = 2 \times X^A$ for deterministic automata over an
alphabet $A$, in three different but equivalent ways: (i) by viewing
context-free grammars as ${\cal D}$-coalgebras; (ii) by defining a
format for behavioural differential equations (w.r.t. ${\cal D}$) for
which the unique solutions are precisely the context-free languages; and
(iii) as the ${\cal D}$-coalgebra of generalized regular expressions in
which the Kleene star is replaced by a unique fixed point operator. In
all cases, semantics is defined by the unique homomorphism into the
final coalgebra of all languages, thus paving the way for coinductive
proofs of context-free language equivalence. Furthermore, the three
characterizations are elementary to the extent that they can serve as
the basis for the definition of a general coalgebraic notion of
context-freeness, which we see as the ultimate long-term goal of the
present study. |
| Publicatie |
https://repository.cwi.nl/noauth/search/fullrecord.php?publn... |
| Persistent Identifier |
urn:NBN:nl:ui:18-18032 |
| Metadata |
XML |
| Repository |
NWO |