4lang is a theory for representing language meaning and also a software library for building and working with such representations. The principal investigator of the 4lang project is Andras Kornai.

Papers

The central publications about 4lang are

• Kornai 2010 and Kornai 2012 lay out the theoretical foundations.

• Kornai et al. 2015 compares 4lang with other theories of lexical semantics

• Kornai et al. 2012 describes an earlier version of the 4lang system and its applications to natural language understanding.

Software

The 4lang library builds and manipulates directed graphs of concepts that represent the meaning of words, phrases and sentences. 4lang can be used to

• build concept graphs from plain text (text_to_4lang)
• build concept graphs from dictionary definitions (dict_to_4lang)
• measure semantic similarity of concept graphs
• measure entailment between concept graphs (experimental)

4lang is available on GitHub under an MIT license. The repository also contains the 4lang concept dictionary.

Documentation

For instructions on using 4lang, see its README

Applications

4lang was used in our system at the Semeval2015 textual similarity task, described in Recski & Ács 2015

Citing

See the README for suggestions on how to cite 4lang

Contact

The 4lang library is maintained by Gábor Recski, who can be reached at "recski at mokk dot bme dot hu".