Juglans nigra English or Persian walnut, but thrives best in the warmer regions of fertile, lowland soils with high water tables, although it will also grow in drier soils, but much more slowly. Some soils preferred by black walnut include Alfisol and Entisol soil types. Walnut grows best on sandy loam, loam, or silt loam type soils but will also grow well on silty clay loam soils. It prefers these soils because they hold large quantities of water which the tree draws from during dry periods. Visually, black walnut is similar to the butternut ("Juglans cinerea") in leaf shape, and the range
Two-sided market that the greater the multihoming costs, the greater is the tendency toward market concentration. Higher multihoming costs reduce user willingness to maintain affiliation with competing networks providing similar services. Attracted by the prospects of large margins, platforms can try to compete to be the winner-take-all in two-sided markets with strong network effects. That means that one platform serves the mature networked market. Examples of the standards battles include VHS vs Betamax, Microsoft vs Netscape and the DVD market. Not all two-sided markets with strong positive network effects are optimially supplied by a single platform. Markets must have high multi-homing costs