For those who don't know the definition: "In economics, a public good is a good that is both non-excludable and non-rivalrous" "A good is considered non-rival

For those who don't know the definition: "In economics, a public good is a good that is both non-excludable and non-rivalrous" "A good is considered non-rivalrous ... if, for any level of production, the cost of providing it to a marginal (additional) individual is zero" "... a good or service is non-excludable if non-paying consumers cannot be prevented from accessing it."