# The meaning of “closed by Maxwell's Equations”?

I am reading some lecture notes (the context is the Vlasov–Landau equation but this is irrelevant for this question) and the phrase came up that the equation was "closed by Maxwell's Equations". A quick Google search shows me that this is quite a common phrasing. I can't, however, seem to find an explanation of what it actually means. Therefore my question is this:

What does it mean for an equation to be closed by Maxwell's equations?

• Hi Q.S., I do believe context is relevant for this question. Do you think you could specify where you read that? Thanks! – AccidentalFourierTransform Jul 24 '17 at 12:46
• @AccidentalFourierTransform The notes themselves arnt' publicly accessible. But the content is simply saying that the Vlasov–Landau equation is closed by Maxwell's Equations. – Quantum spaghettification Jul 24 '17 at 12:53
• +1 thanks for asking about this, questions like yours above help with the jargon I am supposed to know. I deleted my guess. – user163104 Jul 24 '17 at 13:43
• Are you sure the text says that the equation is closed, as opposed to saying that some differential form appearing in that equation is closed? – WillO Jul 24 '17 at 15:43
• @WillO I am pretty sure it is referring to the equation. The wording in my previous comment is almost verbatim from the text. – Quantum spaghettification Jul 24 '17 at 15:58