XML: Foundations, Techniques, Applications; Summer 2000
 
Solution to Problem 8:                Harold Boley <boley@informatik.uni-kl.de>
July 7, 2000


a) Well-formed XML element: Yes


b) Directed labeled graph (DLG):

                           ------------------
                          /                  \
               --------->| http://www.dfki.de |<---------
              /           \                  /           \
             /             ------------------             \
      hosts /            / C|       C|     C| \            \ hosts
           /          A /   |        | field|  \ A          \
          /            /    | founded|      |   \            \
         /            / name|        |      |    \            \
        /     campus /      v        v      v     \ campus     \
      A |           /      ----    ----    --      \           | A
        |          /      |DFKI|  |1988|  |AI|      \          |
        |          |       ----    ----    --       |          |
        |          v                                v          |
  --------------------                            --------------------------
 /                    \                          /                          \
| http://www.uni-kl.de |                        | http://www.uni-saarland.de |
 \                    /                          \                          /
  -------------------- \                        / --------------------------
    C |                C\    ----     ----     /C                     | C
 name |          founded -->|1970|   |1948|<--- founded               | name
      v                      ----     ----                            v
 --------------------------                        --------------------------
|Universität Kaiserslautern|                      |Universität des Saarlandes|
 --------------------------                        --------------------------


c) See b): "C" on content arcs and an "A" on attribute arcs

"Content arcs are targeting RDF literals"
"Attribute arcs are targeting RDF resources"


d) Kind of graph:

Node-labeled tree: No

DAG (directed acyclic graph): No

Directed graph: Yes


e) Prolog facts:

name("http://www.dfki.de","DFKI").
founded("http://www.dfki.de","1988").
field("http://www.dfki.de","AI").
campus("http://www.dfki.de","http://www.uni-kl.de").
campus("http://www.dfki.de","http://www.uni-saarland.de").

name("http://www.uni-kl.de","Universität Kaiserslautern").
founded("http://www.uni-kl.de","1970").
hosts("http://www.uni-kl.de","http://www.dfki.de").

name("http://www.uni-saarland.de","Universität des Saarlandes").
founded("http://www.uni-saarland.de","1948").
hosts("http://www.uni-saarland.de","http://www.dfki.de").


f) Special cases of Horn facts:

Ground facts (without variables as arguments): All, yes

Numeric facts (all arguments are numbers): All, no

Binary facts (2-argument facts): All, yes

Datalog facts (without constructor terms as arguments): All, yes

Modal facts (make assertions about embedded propositions): All, no