3 Aggregate Supply in the Short Run In the real world,many prices are sticky in the short run. For now (and throughout Chapters 9-12),we assume that all prices are stuck at a predetermined level in the short run. .and that firms are willing to sell as much as their customers are willing to buy at that price level. Therefore,the short-run aggregate supply (SRAS)curve is horizontal: CHAPTER 9 Introduction to Economic Fluctuations slide 16slide 16 § In the real world, many prices are sticky in the short run. § For now (and throughout Chapters 9-12), we assume that all prices are stuck at a predetermined level in the short run. § .and that firms are willing to sell as much as their customers are willing to buy at that price level. § Therefore, the short-run aggregate supply (SRAS) curve is horizontal: 3