Talk:Energy functional

Functional?
The explanation of why it's called energy functional instead of energy function is not very clear. Isn't it just a function from the set of states (state space) to the reals? Given that there is no assumptions on the state space being a vector space, there doesn't seem to be any good reason to say it's a functional. The only argument in the article to call it a functional is that "a state of the system is often described as an element of an appropriate function space" but that is not true (and should be removed) and even if it was true "often" isn't the same as "always". Moreover, examples can be found in the literature where it's called energy function but I haven't found any sources where it's called functional. --Ricardohz (talk) 21:25, 23 November 2016 (UTC)