A Relational Algebra for Basic Terms in a Higher-Order Logic

We define a relational algebra on basic terms, strongly typed terms in a higher-order logic, that are well suited to the representation of heterogeneous data, irrespective of whether the data originated from relational, unstructured, semi-structured or structured sources. This higher-order generalisation of the relational model has potential applications in NoSQL databases and Big Variety, Big Data applications.