The Solow-Swan model is an economic theory that explains long-term economic growth by focusing on capital accumulation, labor or population growth, and technological progress. It suggests that an economy's output depends on the amount of capital and labor available, as well as the efficiency of production. The model emphasizes the role of savings and investment in increasing capital stock, which in turn boosts productivity. A key feature of the Solow-Swan model is the concept of diminishing returns, meaning that as more capital is added, the additional output generated from each new unit of capital decreases. This model also highlights the importance of technological advancement, which can lead to sustained growth even when capital accumulation slows down.