MOSG: Multilingual Online Semantics for GF
Björn Bringert
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= Overview =

- System similar to Helpful Curt by Blackburn and Bos.
  - Accepts facts.
  - Filters out uninformative and inconsistent interpretations.
  - Answers Yes/No and WH-questions.
- GF for parsing.
- Multilingual.
- Web-based interface.
- Written in Haskell.
- Answers wh-questions in a new way.


= Syntax =

- Uses a subset of the GF resource grammar library as the
  grammar.
- Multilingual, should work with any language for which there 
  is a resource grammar: 
  Danish, English, Finnish, French, German, Italian, 
  Norwegian, Russian, Spanish, Swedish


= Semantics =

- Statically typed.
- Uses Haskell's lambda expressions directly.
- Uses higher-order abstract syntax for first-order logic.


= Quantifier scope =

- Uses a statically typed implementation of Keller storage.


= FOL tools usage =

- Uses Paradox and Equinox for checking fact equivalence,
  informativity and consistency, and for answering YES/No questions.
- Uses Otter to answer Yes/No questions.
  - Done with "answer predicates" (not yet supported by Equinox), 
    unlike Curt which queries a generated model.
  - This lets us get exhaustive answers, for example with disjunction
    in the theory.


= User interface =

- Several user interfaces: Web-based, command-line, IRC


= Limitations =

== Excluded resource grammar constructs ==

- Tense
- Anteriority
- Sentence-modifying adverbs, except those with subjunctions
- Temporal adverbs
- Many other adverbs
- Adjective-complement verbs.
- Sentence-complement verbs.
- Verb phrase-complement verbs.
- Generalized quantifiers: few, many, much
- Demonstratives: this, that, these
- Personal and possesive pronouns


== Problematic resource grammar constructs ==

- Plurals, e.g. "men are tall", 
  "there are men in the room", "John sees men".  
- Mass nouns have the same problems
- Predeterminers: all, only


== Unimplemented resource grammar constructs ==

- Comparative and superlative forms of adjectives. 
  Introduce more_<adj> predicates?
- Cardinals. "two men sleep" should translate to 
  "exist X. man(X) & exist Y. man(Y) & X != Y & (forall Z. man(Z) => Z == X | Z == Y) & sleep(X) & sleep(Y)"
- Ordinals.


== Underspecification ==

- Scope restrictions.
- Negation scope.


== Problems in the resource grammar ==

- No possessive relative pronoun: "the man whose dog John beats"
- No restrictive pronouns, e.g. "those who sleep", "everyone who sleeps"
- Reciprocal "john and mary met"
- "john gambling is beautiful"
- PN modifying a N: "nobel prize", "itel computer"
- AP modifying PN: "southern europe"
- Subjunctive for QS: "if john sleeps, does mary sleep?"
- Time expressions:
  every week/month/year
  at a quarter past five
  in two years
  in two hours
- Can't say "at least a few"
- "one of"

== Missing from the lexicon ==

out
used to

== Other problems ==

Uppser/lower case. Currently we make the whole input lower case
because we can't handle the sentence initial upper case letter.
This causes problems with words that are upper-case in the grammar,
e.g. I, Monday, etc.