[ttoinou]

Maths have nothing to do with economics. I said efficiency as a way of comparing market offer from the point of view of customers (you can picture the formula "quality/price" if you want but that doesn't mean that it is objectively & mathematically defined), meaning that prices go down and/or quality increases

   mis-configured regulation

Do you have examples of good protectionist regulation ?

And no I gave a specific example with software patents so even if the US is big enough it can benefits from outside products

[Can_Not]

If we're talking about efficiency from the customer point of view, I can pay full price for American goods on Amazon but receive garbage-cheap Chinese knock-offs in the mail.

[ttoinou]

I don't even understand what you are trying to prove. That some sellers are not trust worthy ? That there will always be an intermediary taking the profit ?