戰昇的部落格

以下是Week 12的課程內容摘要與心得，今天的講義包括「Static Oligopoly」與「Dynamic Oligopoly」，內容涵蓋了Bertrand模型、Stackelberg-Cournot模型，以及市場力量的策略應用。

一、靜態寡占市場（Static Oligopoly）

1. Bertrand競爭與價格設置

- 在Bertrand模型中，廠商基於價格競爭，價格會下降到接近完全競爭的水準。

- 當產品具有差異性時，廠商可以設定更高的價格，獲得更高利潤。

2. Cournot模型

- 廠商基於產量決策的模型，均衡產量由邊際收益等於邊際成本決定。

- 相較於Bertrand競爭，Cournot模型下的利潤較高，但仍低於壟斷市場。

3. 均衡特徵

- 靜態模型中的均衡導致市場力量受到一定限制，但仍存在社會福利損失。

二、動態寡占市場（Dynamic Oligopoly）

1. Stackelberg-Cournot模型

- 領導者首先決定產量，追隨者在觀察後再進行決策。

- 領導者利用先發優勢設定更高的產量，迫使追隨者調整行為。

2. 策略應用：潛在進入者威脅

- 為防止新廠商進入市場，既有廠商可能採取過量生產以壓低價格。

- 此策略雖犧牲部分利潤，但能避免競爭加劇。

3. 政策與福利分析

- 當市場接近壟斷但存在潛在競爭者時，價格較壟斷價格低，社會福利改善。

- 比較分析顯示，潛在進入者對市場的影響可能帶來消費者剩餘的提升。

心得總結

這週的課程讓我對寡占市場中不同模型的差異與應用有了更深入的理解。Bertrand模型和Cournot模型揭示了市場結構如何影響廠商策略，而Stackelberg模型則展示了先發優勢在動態市場中的重要性。

特別是潛在進入者的影響部分，課堂內容結合了理論與實際案例，讓我認識到策略性生產決策對市場結果的深遠影響。不過，我在分析Stackelberg模型的數學推導時仍有困難，希望透過課後練習來強化這部分的理解。

Below is the summary and reflection for Week 12. Today’s lecture included Static Oligopoly and Dynamic Oligopoly, covering topics such as the Bertrand model, the Stackelberg-Cournot model, and strategic applications of market power.

A. Static Oligopoly

1. Bertrand Competition and Pricing

- In the Bertrand model, firms compete based on price, driving prices down to levels close to perfect competition.

- When products are differentiated, firms can set higher prices and achieve greater profits.

2. Cournot Model

- A model where firms compete by deciding production quantities, with equilibrium output determined by marginal revenue equaling marginal cost.

- Profits in the Cournot model are higher than in Bertrand competition but lower than in monopoly markets.

3. Equilibrium Characteristics

- Equilibria in static models limit market power to some extent but still result in social welfare losses.

B. Dynamic Oligopoly

1. Stackelberg-Cournot Model

- The leader firm sets its production quantity first, while follower firms adjust their output after observing the leader's decision.

- Leaders use their first-mover advantage to produce higher quantities, forcing followers to adjust their behavior.

2. Strategic Applications: Threat of Potential Entrants

- To deter new firms from entering the market, incumbents may overproduce to lower prices.

- This strategy sacrifices some profits but prevents intensified competition in the long term.

3. Policy and Welfare Analysis

- When markets approach monopoly conditions but face potential competition, prices tend to be lower than monopoly levels, improving social welfare.

- Comparative analysis shows that the presence of potential entrants can enhance consumer surplus.

Reflection Summary

This week’s lecture gave me a deeper understanding of the differences and applications of various oligopoly models. The Bertrand and Cournot models highlighted how market structures influence firm strategies, while the Stackelberg model illustrated the importance of first-mover advantages in dynamic markets.

The section on the impact of potential entrants was particularly insightful, combining theory with real-world examples to demonstrate how strategic production decisions can profoundly influence market outcomes. However, I found the mathematical derivations of the Stackelberg model challenging and hope to strengthen my understanding through additional practice after class.