This paper proposes how to propositional, grammatical, modal and textual meaning may be encoded using a layered approach.

1. Et Tu Brutus? Topic Maps and
Discourse Semantics
TM as a semantic technology

2. Brutus killed Cesar with a dagger.
Clearly, although Cesar must have seen, when
entering the Senate in Rome on the Ides of March
in 44 BC that Brutus, aka Marcus Junius Brutus,
was cheesed off because he had chatted up
Porcia, Brutus’ wife, he did not expect that he
might be brutally murdered by Brutus with a
dagger. He had, therefore, not bought Band-Aid
at Forum Romanum, although the market was
open on that day, it being a weekday.

3. Modeling discourse: information about
• Some possible world or domain
• Some speaker’s or writer’s view of that world
• And the way this speaker or writer has chosen
to structure and convey this information on a
particular occasion.

4. Discourse meaning
• Propositional meaning
• Grammatical meaning
• Modal meaning
• Textual meaning

5. Discourse meaning
• Propositional meaning typically involves real world entities,
events and situations and should therefore, as default, be
encoded using topics and associations.
• Grammatical meaning typically represents properties of real
world entities, events and situations and should therefore, as
default, be encoded using internal occurrences.
• Modal meaning typically reflects the validity of statements on
the part of the speaker or writer and should therefore, as
default, be encoded using scope.
• Textual meaning is typically used to facilitate the elaboration,
enhancement or extension of information and should
therefore, as default, be encoded using reification.

6. Propositional meaning I
Brutus killed Cesar mercilessly with a dagger in
the Senate on the Ides of March
kill(agent : brutus, goal : cesar, instrument :
dagger, manner : mercilessly, place : senate, time
: ides)

7. Propositional meaning II
Brutus killed Cesar mercilessly with a dagger in the Senate
on the Ides of March
Brutus killed Cesar mercilessly with a dagger on the Ides of
March in the Senate
* Brutus killed Cesar in the Senate on the Ides of March
with a dagger mercilessly

8. Propositional meaning III
a) kill(agent : brutus, goal : cesar) ~brutus-kill-cesar
#Brutus kill Cesar
b) proposition(nucleus : brutus-kill-cesar, manner : mercilessly,
instrument : dagger) ~brutus-kill-cesar-mercilessly-with-a-dagger
#Brutus kill Cesar mercilessly with a dagger
c) proposition(nucleus : brutus-kill-cesar-mercilessly-with-a-
dagger, time : ides, place: senate)
#Brutus kill Cesar mercilessly with a dagger on the Ides of March
in the Senate

9. Grammatical meaning
kill(agent : brutus, goal : cesar, instrument : dagger
~instrument-dagger) ~brutus-kill-cesar-with-dagger
brutus-kill-cesar-with-dagger
tense: "past";
aspect: "imperfective".
instrument-dagger is a dagger
definiteness: "definite".
dagger.

10. Modal meaning I
kill(agent : brutus, goal : cesar) ~brutus-kill-cesar
@probability
brutus-kill-cesar
tense: "past ".
#Brutus may have killed Cesar
kill(agent : brutus, goal : cesar) ~brutus-kill-cesar
@likelihood
brutus-kill-cesar
tense: "future".
#Brutus will probably kill Cesar

11. Modal meaning II
No way, Brutus may have killed Cesar

12. Textual meaning I
a) Brutus was cheesed off because Cesar had chatted up
Porcia.
b) Cesar expected an attack. Therefore, he had bought
Band-Aid.
c) Brutus killed Cesar. Then he fled Rome. It was one
mistake after another.

13. Textual meaning II
Brutus was cheesed off because Cesar had chatted up
Porcia.
cheesed-off(subject : brutus, reason : cesar-chatting-
up-porcia)

14. Textual meaning III
Cesar expected an attack. Therefore, he had bought
Band-Aid
reason-result(reason : cesar-expecting-attack, result :
cesar-buying-band-aid)

15. Textual meaning IV
Brutus killed Cesar. Then he fled Rome. It was one
mistake after another.
time-sequence(before : brutus-killing-cesar, after :
brutus-fleeing-rome) ~brutus-killing-cesar-and-then-
fleeing-rome
evaluation(evaluated : brutus-killing-cesar-and-then-
fleeing-rome, evaluation : one-mistake-after-another)

16. Other discourse phenomena
• Appositions and genitives (e.g. Cesar had
chatted up Porcia, Brutus’ wife)
• Cohesion (e.g. the fact that the Ides of March
in 44 BC, on that day and it refer to the same
thing and that Forum Romanum is also the
market)

17. Reifying role playing topics
Cesar chatted up Porcia, Brutus’ wife
married(husband : brutus, wife : porcia ~wifeporcia)
chat-up(agent : cesar, goal : wifeporcia) ~cesar-
chatting-up-porcia

18. Why encode discourse in TM?
• Discourse as topic maps (i.e. discourse is prior
to the topic map).
• Topic maps as discourse (topic map is prior to
discourse)