On the Relation Between Fine-Tuning, Topological Properties, and Task Performance in Sense-Enhanced Embeddings

Topological properties of embeddings, such as isotropy and uniformity, are closely linked to their expressiveness, and improving these properties enhances the embeddings' ability to capture nuanced semantic distinctions. However, fine-tuning can reduce the expressiveness of the embeddings of language models. This study investigates the relation between fine-tuning, topology of the embedding space, and task performance in the context of sense knowledge enhancement, focusing on identifying the topological properties that contribute to the success of sense-enhanced embeddings. We experiment with two fine-tuning methods: Supervised Contrastive Learning (SCL) and Supervised Predictive Learning (SPL). Our results show that SPL, the most standard approach, exhibits varying effectiveness depending on the language model and is inconsistent in producing successful sense-enhanced embeddings. In contrast, SCL achieves this consistently. Furthermore, while the embeddings with only increased sense-alignment show reduced task performance, those that also exhibit high isotropy and balance uniformity with sense-alignment achieve the best results. Additionally, our findings indicate that supervised and unsupervised tasks benefit from these topological properties to varying degrees.