This paper describes the first version of an open-source semantic parser that creates graphical r... more This paper describes the first version of an open-source semantic parser that creates graphical representations of sentences to be used for further semantic processing, e.g. for natural language inference, reasoning and semantic similarity. The Graphical Knowledge Representation which is output by the parser is inspired by the Abstract Knowledge Representation, which separates out conceptual and contextual levels of representation that deal respectively with the subject matter of a sentence and its existential commitments. Our representation is a layered graph with each subgraph holding different kinds of information, including one sub-graph for concepts and one for contexts. Our first evaluation of the system shows an F-score of 85% in accurately representing sentences as semantic graphs. 1 AKR is the semantic component of the XLE platform (Maxwell and Kaplan, 1996)
A position paper arguing that purely graphical representations for natural language semantics lac... more A position paper arguing that purely graphical representations for natural language semantics lack a fundamental degree of expressiveness, and cannot deal with even basic Boolean operations like negation or disjunction, let alone intensional phenomena. Moving from graphs to named graphs leads to representations that stand some chance of having sufficient expressive power. Named F L 0 graphs are of particular interest.
This thesis deals with the patterns of temporal reference exhibited by conditional and modal sent... more This thesis deals with the patterns of temporal reference exhibited by conditional and modal sentences in English, and specifically with the way that past and present tenses can undergo deictic shift in these contexts. This shifting behaviour has consequences both for the semantics of tense and for the semantics of conditionals and modality. Asymmetries in the behaviour of the past and present tenses under deictic shift are explained by positing a primary and secondary deictic centre for tenses. The two deictic centres, the assertion time and the verification time, are given independent motivation through an information based view of tense. This holds that the tense system not only serves to describe the way that the world changes over time, but also the way that information about the world changes. Information change takes place in two stages. First, it is asserted that some fact holds. And then, either at the same time or later, it is verified that is assertion is correct. Typical...
This paper proposes a layered semantic graph representation for dialogue information. The represe... more This paper proposes a layered semantic graph representation for dialogue information. The representation factors information into several interdependent layers, facilitating efficient information access and processing by the components in a dialogue system. We describe the layers in the semantic graph and the function they serve in an implemented task-oriented dialogue system.
Proceedings of the Seventh Joint Conference on Lexical and Computational Semantics, 2018
A position paper arguing that purely graphical representations for natural language semantics lac... more A position paper arguing that purely graphical representations for natural language semantics lack a fundamental degree of expressiveness, and cannot deal with even basic Boolean operations like negation or disjunction, let alone intensional phenomena. Moving from graphs to named graphs leads to representations that stand some chance of having sufficient expressive power. Named F L 0 graphs are of particular interest.
Proceedings of the Workshop on Computational Semantics beyond Events and Roles, 2018
This paper describes the first version of an open-source semantic parser that creates graphical r... more This paper describes the first version of an open-source semantic parser that creates graphical representations of sentences to be used for further semantic processing, e.g. for natural language inference, reasoning and semantic similarity. The Graphical Knowledge Representation which is output by the parser is inspired by the Abstract Knowledge Representation, which separates out conceptual and contextual levels of representation that deal respectively with the subject matter of a sentence and its existential commitments. Our representation is a layered graph with each subgraph holding different kinds of information, including one sub-graph for concepts and one for contexts. Our first evaluation of the system shows an F-score of 85% in accurately representing sentences as semantic graphs. 1 AKR is the semantic component of the XLE platform
This paper is concerned with the way that past and present tenses undergo deictic shift in condit... more This paper is concerned with the way that past and present tenses undergo deictic shift in conditional (and modal) contexts. Two examples of this are:
... The use of context assignments can be best illustrated by looking at the simple minidiscourse... more ... The use of context assignments can be best illustrated by looking at the simple minidiscourse (56) A man walked. He whistled. ... E-type analyses.) Taking the first sentence, A man walked, we have the following lexical con-structors (57) a: V'scope, R, S. ((Vx. subjl. ...
This document was prepared at the request of the European Commission DG XIII by an ad hoc study g... more This document was prepared at the request of the European Commission DG XIII by an ad hoc study group. It is a draft interim report now being made available in the form in which it was submitted to the Commission. It is not an official European Commission document, and does not reflect the policy of the European Commission.
... Basic temporal representation in LF In developing analyses for the sentence types covered by ... more ... Basic temporal representation in LF In developing analyses for the sentence types covered by the system we used an interval-based tense logic, avoiding the kind of direct reference to events advocated by Parsons [25 ... 3.2.7. Modality Modal auxiliary verbs (must, can ...
It is characteristic of the type of interaction that one would like to be able to have with a pla... more It is characteristic of the type of interaction that one would like to be able to have with a planner that the range and type of potential queries is not predictable in advance, and thus not reducible to choices within some predetermined set of options. Furthermore, it is often desirable to have the planner try out a range of hypothetical or counterfactual situations that could not be represented in any obvious graphical form. An interface to a planner therefore requires some kind of language, either artificial or natural. The paper describes work that has been carried out in investigating the use of natural language for this sort of interface.
Proceedings of the 35th annual meeting on Association for Computational Linguistics -, 1997
We describe a method for interpreting abstract fiat syntactic representations, LFG fstructures, a... more We describe a method for interpreting abstract fiat syntactic representations, LFG fstructures, as underspecified semantic representations, here Underspecified Discourse Representation Structures (UDRSs). The method establishes a one-to-one correspondence between subsets of the LFG and UDRS formalisms. It provides a model theoretic interpretation and an inferential component which operates directly on underspecified representations for fstructures through the translation images of f-structures as UDRSs.
This paper describes the first version of an open-source semantic parser that creates graphical r... more This paper describes the first version of an open-source semantic parser that creates graphical representations of sentences to be used for further semantic processing, e.g. for natural language inference, reasoning and semantic similarity. The Graphical Knowledge Representation which is output by the parser is inspired by the Abstract Knowledge Representation, which separates out conceptual and contextual levels of representation that deal respectively with the subject matter of a sentence and its existential commitments. Our representation is a layered graph with each subgraph holding different kinds of information, including one sub-graph for concepts and one for contexts. Our first evaluation of the system shows an F-score of 85% in accurately representing sentences as semantic graphs. 1 AKR is the semantic component of the XLE platform (Maxwell and Kaplan, 1996)
A position paper arguing that purely graphical representations for natural language semantics lac... more A position paper arguing that purely graphical representations for natural language semantics lack a fundamental degree of expressiveness, and cannot deal with even basic Boolean operations like negation or disjunction, let alone intensional phenomena. Moving from graphs to named graphs leads to representations that stand some chance of having sufficient expressive power. Named F L 0 graphs are of particular interest.
This thesis deals with the patterns of temporal reference exhibited by conditional and modal sent... more This thesis deals with the patterns of temporal reference exhibited by conditional and modal sentences in English, and specifically with the way that past and present tenses can undergo deictic shift in these contexts. This shifting behaviour has consequences both for the semantics of tense and for the semantics of conditionals and modality. Asymmetries in the behaviour of the past and present tenses under deictic shift are explained by positing a primary and secondary deictic centre for tenses. The two deictic centres, the assertion time and the verification time, are given independent motivation through an information based view of tense. This holds that the tense system not only serves to describe the way that the world changes over time, but also the way that information about the world changes. Information change takes place in two stages. First, it is asserted that some fact holds. And then, either at the same time or later, it is verified that is assertion is correct. Typical...
This paper proposes a layered semantic graph representation for dialogue information. The represe... more This paper proposes a layered semantic graph representation for dialogue information. The representation factors information into several interdependent layers, facilitating efficient information access and processing by the components in a dialogue system. We describe the layers in the semantic graph and the function they serve in an implemented task-oriented dialogue system.
Proceedings of the Seventh Joint Conference on Lexical and Computational Semantics, 2018
A position paper arguing that purely graphical representations for natural language semantics lac... more A position paper arguing that purely graphical representations for natural language semantics lack a fundamental degree of expressiveness, and cannot deal with even basic Boolean operations like negation or disjunction, let alone intensional phenomena. Moving from graphs to named graphs leads to representations that stand some chance of having sufficient expressive power. Named F L 0 graphs are of particular interest.
Proceedings of the Workshop on Computational Semantics beyond Events and Roles, 2018
This paper describes the first version of an open-source semantic parser that creates graphical r... more This paper describes the first version of an open-source semantic parser that creates graphical representations of sentences to be used for further semantic processing, e.g. for natural language inference, reasoning and semantic similarity. The Graphical Knowledge Representation which is output by the parser is inspired by the Abstract Knowledge Representation, which separates out conceptual and contextual levels of representation that deal respectively with the subject matter of a sentence and its existential commitments. Our representation is a layered graph with each subgraph holding different kinds of information, including one sub-graph for concepts and one for contexts. Our first evaluation of the system shows an F-score of 85% in accurately representing sentences as semantic graphs. 1 AKR is the semantic component of the XLE platform
This paper is concerned with the way that past and present tenses undergo deictic shift in condit... more This paper is concerned with the way that past and present tenses undergo deictic shift in conditional (and modal) contexts. Two examples of this are:
... The use of context assignments can be best illustrated by looking at the simple minidiscourse... more ... The use of context assignments can be best illustrated by looking at the simple minidiscourse (56) A man walked. He whistled. ... E-type analyses.) Taking the first sentence, A man walked, we have the following lexical con-structors (57) a: V'scope, R, S. ((Vx. subjl. ...
This document was prepared at the request of the European Commission DG XIII by an ad hoc study g... more This document was prepared at the request of the European Commission DG XIII by an ad hoc study group. It is a draft interim report now being made available in the form in which it was submitted to the Commission. It is not an official European Commission document, and does not reflect the policy of the European Commission.
... Basic temporal representation in LF In developing analyses for the sentence types covered by ... more ... Basic temporal representation in LF In developing analyses for the sentence types covered by the system we used an interval-based tense logic, avoiding the kind of direct reference to events advocated by Parsons [25 ... 3.2.7. Modality Modal auxiliary verbs (must, can ...
It is characteristic of the type of interaction that one would like to be able to have with a pla... more It is characteristic of the type of interaction that one would like to be able to have with a planner that the range and type of potential queries is not predictable in advance, and thus not reducible to choices within some predetermined set of options. Furthermore, it is often desirable to have the planner try out a range of hypothetical or counterfactual situations that could not be represented in any obvious graphical form. An interface to a planner therefore requires some kind of language, either artificial or natural. The paper describes work that has been carried out in investigating the use of natural language for this sort of interface.
Proceedings of the 35th annual meeting on Association for Computational Linguistics -, 1997
We describe a method for interpreting abstract fiat syntactic representations, LFG fstructures, a... more We describe a method for interpreting abstract fiat syntactic representations, LFG fstructures, as underspecified semantic representations, here Underspecified Discourse Representation Structures (UDRSs). The method establishes a one-to-one correspondence between subsets of the LFG and UDRS formalisms. It provides a model theoretic interpretation and an inferential component which operates directly on underspecified representations for fstructures through the translation images of f-structures as UDRSs.
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Papers by Richard Crouch