"The generation and implementation of ideas, or knowledge, is crucial for economic performance. We study this process in a model of endogenous growth with frictions. Productivity increases with knowledge, which advances via innovation, and with the exchange of ideas from those who generate them...

We introduce two pieces of information, denoted memes, into a diffusion process in which memes are transmitted when individuals meet and forgotten at an exogenous rate. At most one meme can be transmitted at a meeting, which introduces opportunity costs in the process. Individuals differ...