It's unclear how sulfur works, but it has only a marginal benefit in most cases.

And, if so, what is the marginal benefit of having more than one university?

So each individual pays according to his/her marginal benefit derived from the public good.

"And my suspicion is that higher doses, if effective at all, would be of marginal benefit."

In this case, they are equivalent to the private marginal benefits and costs.

Higher order phase systems require more than three wires, but deliver marginal benefits.

You would compensate your neighbour for the loss of his marginal benefit.

Thus at the output Q the social marginal benefit is.

What is the social marginal benefit of the last unit to the group as a whole?

At the output Q the marginal social benefit is thus.