The document presents a new C-Miner algorithm for efficiently finding the top-k competitors of a given item from large datasets. It proposes a formal definition of competitiveness between two items based on the market segments they can both cover. The C-Miner algorithm uses a pyramid finder technique and dominance relationships to reduce the number of items that need to be considered during computation. It then incrementally calculates competitor scores and prunes items to identify the top-k competitors. The approach provides an effective solution for identifying competitors from large, real-world datasets across different domains.