1 INTRODUCTION

2 DEFINITIONS

3 CONTRIBUTORS TO HALLUCINATION IN NLG

4 METRICS MEASURING HALLUCINATION

5 HALLUCINATION MITIGATION METHODS

6 FUTURE DIRECTIONS

7 HALLUCINATION IN ABSTRACTIVE SUMMARIZATION

8 HALLUCINATION IN DIALOGUE GENERATION

9 HALLUCINATION IN GENERATIVE QUESTION ANSWERING

10 HALLUCINATION IN DATA-TO-TEXT GENERATION

11 HALLUCINATIONS IN NEURAL MACHINE TRANSLATION

12 HALLUCINATION IN VISION-LANGUAGE GENERATION

13 HALLUCINATION IN LARGE LANGUAGE MODELS

14 CONCLUSION