Most western interest-rate determinism focuses on the analysis of supply and demand comparisons, arguing that interest rates are a price. The difference lies in what supply and demand determines interest rates. For example, Marshall's real interest rate theory emphasizes the real factors of non-monetary factors - productivity and the role of economy in determining interest rate decisions. Productivity is expressed by marginal propensity to invest, and the marginal propensity to save is expressed. This may have a negative effect on the sales of Xpoint products. After Ziddu becomes its subsidiary, Longfin will provide financial services based on cryptocurrency through Ziddu. These goals are ambitious, but they also remind us to do one thing in the right way. Cylinder work volume refers to the volume of gas swept by the piston from the top to the bottom, also known as single cylinder displacement, depending on the cylinder diameter and the piston stroke. Engine displacement is the total volume of working volume of each cylinder, usually expressed in milliliter (CC). Engine displacement is one of the most important structural parameters. It is more representative of engine size than cylinder diameter and cylinder number, and many indicators of engine are closely related to displacement. It is not obvious in some analyses, but it is important to note that economic profits include opportunity costs. The profit of an entrepreneur (normal profit) is usually positive, but economic profit can be either positive or negative (loss). That's why the opportunity cost is included: in a completely competitive market, when marginal cost equals marginal revenue, profit maximization or loss minimization conditions arise. If the market price is lower than the total average cost, which means that the economic profit is negative, the entrepreneur needs to compare the value of the loss and the average variable cost. If the business continues to operate, the negative economic profit must not be lower than the average variable cost, otherwise the entrepreneur would rather shut down the company than continue to take the loss. The views of munoz and sprawus