Real world arrays often contain underlying structure, such as sparsity, runs of repeated values, or symmetry. Specializing for structure yields significant speedups. But automatically generating efficient code for structured data is challenging, ...

In this work we present a modular theory of the coalgebras and bisimulation in the intensional type theory implemented in <em>coq</em> . On top of that we build the theory of weakly final coalgebras and develop the <em>λ</em> -coiteration scheme, ...