Terminology

Authors

Tong Zhu

Last Update

Jan. 4th, 2021

Contents

Event Instance

An event instance is a single event in a table format. The table includes event type and several argument roles together with corresponding arguments. The example is shown as below:

Tom bought 2 pounds of flour at Pinshihui for $5 per pound last night.

Event Type: Buy
Buyer	Tom
Object	2 pounds of flour
Price	$5 per pound
Time	last night
Location	Pinshihui
Cashier	N/A

Trigger

Refering the annotation guide of ACE05 1, event trigger is the word that most clearly expresses event’s occurrence. For instance, the trigger word of the example above is bought.

Argument Role

Argument roles are event participants’ types. For instance, Buyer, Object, Price, Time, Location and Cashier are argument roles. These roles are pre-defined together with event types. Each event type correspondes to a specific event template table.

Argument

Arguments are participants to corresponding roles. Arguments can be absent if the context cannot provide the information. For example, we don’t know who is the cashier when Tom bought flour last night, so here the argument to Cashier role is N/A.

Combination

Argument combinations are set without inner argument orders. For example, the combination of the above example is {last night, Tom, $5 per pound, 2 pounds of flour, Pinshihui}. N/A is not included in combinations.

Entity & Mention

Entities are basic elements of objects. For example, Tom is a PERSON entity. One entity may have multiple mentions, and a mention could be an occurrence in the raw text, or a pronoun refering to the same entity.

Span

Span indicates the positions [sentence idx, start char idx, end char idx + 1]. For instance, [0, 1, 3] refers to bought 2 if we apply space tokenisation.

References

1

https://www.ldc.upenn.edu/sites/www.ldc.upenn.edu/files/english-events-guidelines-v5.4.3.pdf