Table 5.1 reflects the four significant categories of industry frameworks and their attributes.

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Table 5.1 Market Structure Characteristics

Free enattempt and also exit | Barriers to entry | No entry | |

Perfect competition is on one finish of the industry framework spectrum, via plenty of firms. Words, “numerous” has actually unique meaning in this context. In a perfectly competitive market, each firm is so little relative to the industry that it cannot influence the price of the great. Each perfectly competitive firm is a price taker. As such, many firms implies that each firm is so little that it is a price taker.

Monopoly is the various other too much of the industry structure spectrum, through a single firm. Monopolies have monopoly power, or the capability to adjust the price of the good. Monopoly power is also referred to as sector power, and is measured by the Lerner Index.

This chapter specifies and also explains two intermediary industry structures: monopolistic competition and oligopoly.

**Monopolistic Competition** = A sector framework identified by a distinguished product and also freedom of entry and exit.

Monopolistically Competitive firms have one characteristic that is prefer a monopoly (a differentiated product provides market power), and one characteristic that is choose a competitive firm (liberty of enattempt and exit). This form of market structure is widespread in market-based economies, and also a trip to the grocery save reveals huge numbers of identified products: toothpaste, laundry soap, breakrapid cereal, and so on.

Next, we define the industry framework **oligopoly**.

**Oligopoly** = A industry structure characterized by barriers to enattempt and a few firms.

Oligopoly is a fascinating sector framework due to interactivity and interdependency between oligopolistic firms. What one firm does affects the other firms in the oligopoly.

Because monopolistic competition and oligopoly are intermediary market structures, the next area will testimonial the properties and features of perfect competition and monopoly. These features will administer the defining characteristics of monopolistic competition and also oligopoly.

*5.1.2 Recheck out of Perfect Competition*

The perfectly competitive sector has actually four characteristics:

(1) Homogenous product,

(2) Large number of buyers and sellers (many firms),

(3) Freedom of entry and exit, and

(4) Perfect information.

The opportunity of entry and departure of firms occurs in the lengthy run, since the number of firms is fixed in the brief run.

An equilibrium is defined as a suggest wright here tright here is no tendency to change. The concept of equilibrium deserve to be extended to incorporate the brief run and also long run.

**Short Run Equilibrium** = A point from which tbelow is no tendency to adjust (a stable state), and a solved variety of firms.

**Long Run Equilibrium** = A point from which tbelow is no tendency to adjust (a stable state), and enattempt and exit of firms.

In the short run, the variety of firms is fixed, whereas in the long run, entry and exit of firms is feasible, based on profit conditions. We will certainly compare the brief and also lengthy run for a competitive firm in Figure 5.1. The two panels in Figure 5.1 are for the firm (left) and market (right), with vastly various units. This is emphasized by using “q” for the firm’s output level, and “Q” for the sector output level. The graph reflects both brief run and lengthy run equilibria for a perfectly competitive firm and industry. In short run equilibrium, the firms faces a high price (PSR), produces quantity QSR at PSR = MC, and earns positive earnings πSR.

Figure 5.1 Quick Run and also Long Run Equilibria for a Perfectly Competitive Firm

Positive profits in the short run (πSR > 0) lead to entry of other firms, as tright here are no barriers to enattempt in a competitive market. The enattempt of brand-new firms shifts the supply curve in the market graph from supply SSR to supply SLR. Entry will take place until revenues are thrust to zero, and also lengthy run equilibrium is got to at Q*LR. In the lengthy run, financial profits are equal to zero, so there is no inspiration for entry or exit. Each firm is earning precisely what it is worth, the opportunity prices of all resources. In lengthy run equilibrium, earnings are zero (πLR = 0), and also price equates to the minimum average cost allude (P = min AC = MC). Marginal costs equal average expenses at the minimum average expense point. At the lengthy run price, supply equals demand also at price PLR.

*5.1.3 Recheck out of Monopoly*

The attributes of monopoly include: (1) one firm, (2) one product, and also (3) no enattempt (Table 5.1). The monopoly solution is displayed in Figure 5.2.

Figure 5.2 Monopoly Profit Maximization

Keep in mind that long-run revenues can exist for a monopoly, considering that barriers to entry halt any kind of potential entrants from joining the market. In the following section, we will check out industry structures that lie between the two extremes of perfect competition and monopoly.

5.2 Monopolistic CompetitionMonopolistic competition is a industry framework identified by cost-free enattempt and leave, prefer competition, and identified assets, favor monopoly. Differentiated products administer each firm via some sector power. Advertising and also marketing of each individual product carry out uniqueness that reasons the demand curve of each excellent to be downward sloping. Free entry suggests that each firm competes through other firms and profits are equal to zero on lengthy run equilibrium. If a monopolistically competitive firm is earning positive economic earnings, enattempt will happen till economic revenues are equal to zero.

*5.2.1 Monopolistic Competition in the Short and Long Runs*

The demand curve of a monopolistically competitive firm is downward sloping, indicating that the firm has actually a level of sector power. Market power derives from product differentiation, because each firm produces a different product. Each great has actually many kind of cshed substitutes, so industry power is limited: if the price is increased also much, consumers will certainly transition to competitors’ assets.

Figure 5.3 Monopolistic Competition in the Brief Run and also Long Run

Short and long run equilibria for the monopolistically competitive firm are presented in Figure 5.3. The demand also curve facing the firm is downward sloping, yet fairly elastic due to the availability of cshed substitutes. The short run equilibrium appears in the left hand also panel, and also is practically identical to the monopoly graph. The only difference is that for a monopolistically competitive firm, the demand is relatively elastic, or flat. Otherwise, the brief run profit-maximizing solution is the very same as a monopoly. The firm sets marginal revenue equal to marginal expense, produces output level q*SR and charges price PSR. The profit level is displayed by the shaded rectangle π.

The long run equilibrium is presented in the best hand also panel. Entry of other firms occurs till earnings are equal to zero; complete profits are equal to complete prices. Thus, the demand also curve is tangent to the average expense curve at the optimal long run amount, q*LR. The lengthy run profit-maximizing amount is uncovered wright here marginal revenue amounts to marginal price, which likewise occurs at q*LR.

*5.2.2 Economic Efficiency and Monopolistic Competition*

Tbelow are two sources of inefficiency in monopolistic competition. First, dead weight loss (DWL) as a result of monopoly power: price is better than marginal expense (P > MC). 2nd, excess capacity: the equilibrium amount is smaller than the lowest price quantity at the minimum point on the average expense curve (q*LR minAC). These 2 sources of inefficiency have the right to be viewed in Figure 5.4.

Figure 5.4 Comparison of Efficiency for Competition and also Monopolistic Competition

First, there is dead weight loss (DWL) as a result of industry power: the price is higher than marginal price in lengthy run equilibrium. In the best hand panel of Figure 5.4, the price at the lengthy run equilibrium amount is PLR, and marginal price is lower: PLR > MC. This reasons dead weight loss to society, considering that the competitive equilibrium would be at a bigger amount wbelow P = MC. Total dead weight loss is the shaded area beneath the demand curve and also over the MC curve in figure 5.4.

The second source of inefficiency linked with monopolistic competition is excess capacity. This have the right to likewise be viewed in the appropriate hand panel of Figure 5.4, wright here the long run equilibrium quantity is lower than the quantity wbelow average expenses are lowest (qminAC). Therefore, the firm can produce at a reduced expense by enhancing output to the level where average costs are decreased.

Given these 2 inefficiencies associated with monopolistic competition, some people and teams have dubbed for government treatment. Regulation can be supplied to mitigate or eliminate the inefficiencies by rerelocating product differentiation. This would certainly cause a solitary product instead of a big number of close substitutes.

Regulation is more than likely not an excellent solution to the inefficiencies of monopolistic competition, for two factors. First, the sector power of a typical firm in a lot of monopolistically competitive markets is small. Each monopolistically competitive market has many kind of firms that create sufficiently substitutable assets to administer enough competition to lead to relatively low levels of sector power. If the firms have small levels of market power, then the deadweight loss and excess capacity inefficiencies are likely to be small.

Second, the benefit gave by monopolistic competition is product diversity. The gain from product diversity deserve to be huge, as consumers are willing to pay for various attributes and also qualities. As such, the get from product diversity is most likely to outweigh the expenses of inefficiency. Evidence for this case can be checked out in market-based economic climates, where there is a vast amount of product diversity.

The following chapter will present and also comment on oligopoly: strategic interactions between firms!

5.3 Oligopoly ModelsAn oligopoly is identified as a market structure with few firms and barriers to enattempt.

**Oligopoly** = A market structure via few firms and also barriers to entry.

Tbelow is regularly a high level of competition in between firms, as each firm renders decisions on prices, amounts, and heralding to maximize revenues. Due to the fact that tright here are a small variety of firms in an oligopoly, each firm’s profit level counts not just on the firm’s own decisions, but additionally on the decisions of the various other firms in the oligopolistic market.

*5.3.1 Strategic Interactions*

Each firm need to take into consideration both: (1) other firms’ reactions to a firm’s very own decisions, and (2) the very own firm’s reactions to the various other firms’ decisions. Thus, tright here is a constant interplay in between decisions and reactions to those decisions by all firms in the sector. Each oligopolist should take right into account these strategic interactions as soon as making decisions. Since all firms in an oligopoly have outcomes that depend on the various other firms, these strategic interactions are the foundation of the study and also understanding of oligopoly.

For instance, each automobile firm’s industry share relies on the prices and amounts of all of the various other firms in the market. If Ford lowers prices family member to other automobile manufacturers, it will certainly boost its market share at the expense of the various other auto suppliers.

When making decisions that consider the feasible reactions of other firms, firm managers usually assume that the managers of contending firms are rational and intelligent. These strategic interactions develop the study of game theory, the topic of Chapter 6 below. John Nash (1928-2015), an Amerideserve to mathematician, was a pioneer in game theory. Economists and mathematicians use the idea of a Nash Equilibrium (NE) to describe a common outcome in game theory that is typically supplied in the research of oligopoly.

** Nash Equilibrium** = An outcome where tbelow is no tendency to adjust based on each individual picking a strategy provided the strategy of rivals.

In the research of oligopoly, the Nash Equilibrium assumes that each firm renders rational profit-maximizing decisions while holding the habits of rival firms consistent. This presumption is made to simplify oligopoly models, provided the potential for enormous intricacy of strategic interactions between firms. As an aside, this assumption is among the exciting themes of the activity image, “A Beautiful Mind,” starring Rusoffer Crowe as John Nash. The concept of Nash Equilibrium is also the foundation of the models of oligopoly presented in the following 3 sections: the Cournot, Bertrand, and Stackelberg models of oligopoly.

*5.3.2 Cournot Model*

Augustin Cournot (1801-1877), a French mathematician, emerged the first model of oligopoly explored below. The Cournot version is a version of oligopoly in which firms develop a homogeneous good, assuming that the competitor’s output is fixed as soon as deciding exactly how a lot to develop.

A numerical example of the Cournot version complies with, wright here it is assumed that tbelow are two similar firms (a duopoly), through output provided by Qi (i=1,2). Therefore, total market output is equal to: Q = Q1 + Q2. Market demand also is a function of price and offered by Qd = Qd(P), therefore the inverse demand also function is P = P(Qd). Note that the price depends on the industry output Q, which is the sum of both individual firm’s outputs. In this means, each firm’s output has actually an influence on the price and earnings of both firms. This is the basis for strategic interactivity in the Cournot model: if one firm rises output, it lowers the price dealing with both firms. The inverse demand also feature and also expense attribute are provided in Equation 5.1.

(5.1) P = 40 – QC(Qi) = 7Qi i = 1,2

Each firm chooses the optimal, profit-maximizing output level provided the various other firm’s output. This will result in a Nash Equilibrium, since each firm is holding the actions of the rival consistent. Firm One maximizes revenues as follows.

max π1 = TR1 – TC1

max π1 = P(Q)Q1 – C(Q1)

max π1 = <40 – Q>Q1 – 7Q1

max π1 = <40 – Q1 – Q2>Q1 – 7Q1

max π1 = 40Q1 – Q12 – Q2Q1 – 7Q1

∂π1/∂Q1= 40 – 2Q1 – Q2 – 7 = 0

2Q1 = 33 – Q2

Q1* = 16.5 – 0.5Q2

This equation is called the “Reactivity Function” of Firm One. This is as far as the mathematical solution have the right to be streamlined, and represents the Cournot solution for Firm One. It is a reactivity attribute because it defines Firm One’s reactivity offered the output level of Firm Two. This equation represents the strategic interactions between the 2 firms, as transforms in Firm Two’s output level will certainly lead to transforms in Firm One’s response. Firm One’s optimal output level relies on Firm Two’s behavior and decision making. Oligopolists are interassociated in both behavior and outcomes.

The two firms are assumed to be identical in this duopoly. Thus, Firm Two’s reactivity function will be symmetrical to the Firm One’s reaction feature (check this by establishing up and solving the profit-maximization equation for Firm Two):

Q2* = 16.5 – 0.5Q1

The 2 reactivity attributes deserve to be supplied to deal with for the Cournot-Nash Equilibrium. Tright here are two equations and 2 unknowns (Q1 and also Q2), so a numerical solution is uncovered via substitution of one equation right into the other.

Q1* = 16.5 – 0.5(16.5 – 0.5Q1)

Q1* = 16.5 – 8.25 + 0.25Q1

Q1* = 8.25 + 0.25Q1

0.75Q1* = 8.25

Q1* = 11

Due to symmeattempt from the presumption of the same firms:

Qi = 11 i = 1,2Q = 22units P = 18 USD/unit

Profits for each firm are:

πi = P(Q)Qi – C(Qi) = 18(11) – 7(11) = (18 – 7)11 = 11(11) = 121 USD

This is the Cournot-Nash solution for oligopoly, discovered by each firm assuming that the various other firm holds its output level continuous. The Cournot model deserve to be easily extfinished to more than two firms, but the math does obtain progressively facility as even more firms are added. Economists utilize the Cournot model because is based upon intuitive and realistic assumptions, and also the Cournot solution is intermediary between the outcomes of the two extreme sector structures of perfect competition and also monopoly.

This can be seen by fixing the numerical instance for competition, Cournot, and monopoly models, and comparing the options for each sector structure.

In a competitive industry, free entry outcomes in price equal to marginal cost (P = MC). In the instance of the numerical example, COMPUTER = 7. When this competitive price is substituted right into the inverse demand equation, 7 = 40 – Q, or Qc = 33. Profits are found by solving (P – MC)Q, or πc = (7 – 7)Q = 0. The competitive solution is offered in Equation (5.2).

(5.2) Pc = 7 USD/unitQc = 33 unitsπc = 0 USD

The monopoly solution is uncovered by maximizing revenues as a solitary firm.

max πm = TRm – TCm

max πm = P(Qm)Qm – C(Qm)

max πm = <40 – Qm>Qm – 7Qm

max πm = 40Qm – Qm2 – 7Qm

∂πm/∂Qm= 40 – 2Qm – 7 = 0

2Qm = 33

Qm* = 16.5

Pm = 40 – 16.5 = 23.5

πm = (Pm – MCm)Qm = (23.5 – 7)16.5 = 16.5(16.5) = 272.25 USD

The monopoly solution is provided in Equation (5.3).

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(5.3) Pm = 23.5 USD/unit Qm = 16.5 unitsπm = 272.5 USD

The competitive, Cournot, and monopoly solutions have the right to be compared on the same graph for the numerical example (Figure 5.5).