Yoneda Lemma in Double Categories

The article discusses the Yoneda Lemma in the context of double categories. Double categories are a generalization of categories that allow for two levels of morphisms, enabling the study of more complex structures. The Yoneda Lemma, a fundamental concept in category theory, has been generalized to the double category setting. The author, Bartosz Milewski, explains how this generalization allows for a more nuanced understanding of the relationships between objects in a double category. He also provides examples and explanations to illustrate the concept.