Explore a 16-minute video presentation from the PLDI 2023 conference introducing indexed streams, a formal operational model and intermediate representation for fused contraction programs. Learn about this novel approach that encompasses both sparse tensor algebra and relational algebra. Discover how the researchers prove the correctness of the indexed stream model and develop a compact 540-line compiler that matches the performance of TACO for sparse tensor algebra and SQLite and DuckDB for relational algebra. Gain insights into the potential applications of this formal intermediate representation in optimizing contraction language execution.