Before revision:  Firms face a choice between secrecy, which protects existing intellectual property, and openness, which facilitates social learning . These decisions determine interaction rates between firms, and these interaction rates enter our model as link probabilities in a resulting learning network.
After revision:  Firms face a choice between secrecy, which protects existing intellectual property, and openness, which facilitates learning from others. Their decisions determine interaction rates between firms, and these interaction rates enter our model as link probabilities in a resulting learning network.