Talk:Inexact differential

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1 Inexact differential?
2 No merging
3 Inexact differential
4 Imperfect Differential

[edit] Inexact differential?

What *is* an inexact differential. I believe I was the person that put that redlink up a long while ago in Entropy (thermodynamic views), and I had hoped that someone would fill that space with an explanation. I still have no idea what the inexact differential symbol δ *means*. Does anyone know? Fresheneesz 09:34, 5 May 2006 (UTC)

Yes, loosely it means that the function may not exist; also in thermodynamics it means that that function is not a state function and that it is path dependent. This is just from memory, I may be off on a few technical points. We are working to build the inexact differential article. Help if you want. Thanks:--Sadi Carnot 13:54, 25 July 2006 (UTC)

[edit] No merging

Please do not attmept to merge this article into exact differential. These are seperate but related terms. See: Talk:First law of thermodynamics for example. Thanks:--Sadi Carnot 05:48, 25 July 2006 (UTC)

[edit] Inexact differential

I stumbled over the first sentence of Inexact differential, because it does not say at all how the "inexact differential" of a function f is defined, and I could not make any sense of it. Since the rest of the article only says that the properties of an inexact differential are the opposite of the properties of an exact differential, which is obvious, I thought it would be best to merge it with exact differential. However, you reverted this. Why? -- Jitse Niesen (talk) 05:54, 25 July 2006 (UTC)

Just saw your comment on Talk:Inexact differential. Will have a look later. -- Jitse Niesen (talk) 05:57, 25 July 2006 (UTC)

Jitse, I assumed your merge was well intentioned in that you were just trying to help organize the math articles. Next time, however, if you feel a merge is needed please put merge tags on both articles and let your written proposal sit on the talk page for a month or so. For the record, I started the exact differential article last year but someone else started the inexact differential article recently. This latter article, has been a redlink on many Wiki pages, such as Entropy (thermodynamic views), for sometime now. It has even been a request on talk pages such as Talk:Entropy (thermodynamic views), Talk:entropy, Talk:heat, and Talk:First law of thermodynamics, to name a few. Certainly, the article may need cleaning and smoothing, but not merging. Please help with this improvement if you will. I will try as well. Thanks: --Sadi Carnot 14:22, 25 July 2006 (UTC)

I will also add some external links; I hope this helps?--Sadi Carnot 14:36, 25 July 2006 (UTC)

i will change "mathematics" to "physics" in the intro, as it is not accurate. it is not a math term or object. as above conversation indicates, a trained mathematician may very well not recognize it. Mct mht 20:29, 19 August 2006 (UTC)

Do we believe an "inexact differential" corresponds to a mathematical object at all? We know that it's mainly thanks to Clausius that thermodynamics as it is traditionally taught employs a mathematics and notation all of its own. But hey, that was in 1880's. Marc Goossens 16:33, 25 October 2006 (UTC)

It is a very common term in thermodynamics; although "exact" probably is used more. Renowned chemical engineer Kenneth Denbigh states in his 1984 The Principles of Chemical Equilibrium, 4th Ed., that "the word 'exact' merely means that the integral is independent of path." (pg. 21). Although, in the notes, he says that this is not the same thing as saying that a differential, or differential expression, is 'complete'. He says, "for example:

$dU = \left( \frac{\partial U}{\partial T} \right) dT + \left( \frac{\partial U}{\partial p} \right) dp$

would be complete only if T and p completely determine the state of the system; in general, U depends also on the size and composition and extra terms must be added." Later: --Sadi Carnot 16:36, 5 November 2006 (UTC)

[edit] Imperfect Differential

I'm not sure how to make a re-direct, so could someone make a redirect from imperfect differential to here? Over in this locale we call it an "imperfect differential". Fephisto 21:36, 24 August 2006 (UTC)

to make a redirect, create a new page, in which you type #REDIRECT [[inexact differential]] . Mct mht 14:08, 26 August 2006 (UTC)