Juglans regia Juglans regia Juglans regia, the Persian walnut, English walnut, Circassian walnut, or especially in Great Britain, common walnut, is an Old World walnut tree species native to the region stretching from the Balkans eastward to the Himalayas and southwest China. The largest forests are in Kyrgyzstan, where trees occur in extensive, nearly pure, walnut forests at 1,000–2,000 m (3000 to 7000 ft) altitude—notably at Arslanbob in Jalal-Abad Province. It is widely cultivated across Europe. "Juglans regia" is a large, deciduous tree attaining heights of 25–35 m (80 to 120 ft), and a trunk up to 2 m (6 ft) diameter,
Two-sided market to invest more in R&D or lower their prices, driving out weaker rivals. As a result, mature two-sided network industries are usually dominated by a handful of large platforms, as is the case in the credit card industry. In extreme situations, such as PC operating systems, a single company emerges as the winner, taking almost all of the market. Platform managers must choose the right price to charge each group in a two-sided network and ignoring network effects can lead to mistakes. In "figure 2", pricing without taking network effects into account means finding prices that maximize the areas of