Which Notation for Partial Derivatives Do You Prefer?

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Discussion Overview

The discussion centers around preferences for notation used in partial derivatives, specifically comparing Spivak's notation to classical notation. Participants explore the implications of these notations in the context of calculus on manifolds, chain rules, and their application in various mathematical contexts.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • One participant expresses a preference for Spivak's notation for partial derivatives, noting its advantages over classical notation, which they find ambiguous.
  • Another participant questions what Spivak's notation entails, indicating a lack of familiarity with it.
  • A participant mentions that understanding the dependency of \frac{\partial}{\partial x^i} on all coordinates is crucial for using classical notation correctly.
  • Spivak's notation is explained by a participant, highlighting how it denotes partial derivatives using D1f and D2f, and contrasts this with classical notation, which can lead to confusion due to the meaning of f changing in different contexts.
  • There is a mention of the utility of Spivak's notation in complex expressions involving multiple functions of variables.

Areas of Agreement / Disagreement

Participants do not reach a consensus on which notation is preferable. There are multiple competing views regarding the clarity and utility of Spivak's notation versus classical notation.

Contextual Notes

Some participants express uncertainty about the implications of using different notations, particularly regarding the dependency of variables and the potential for confusion in interpretation.

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I am currently working through spivak's calculus on manifolds (which i love by the way) in one of my class. my question is about his notation for partial derivatives. i completely understand why he uses it and how the classical notation has some ambiguity to it. however, i can't help but thinking of partial derivatives, the chain rule (from R^n to R), and such in terms of the classical notation that i have used for so long. even my professor, though he sometimes uses spivak's notation, slips into the classical notation, especially when he is lecturing without notes.
my question is what notation do you prefer? i haven't seen spivak's notation anywhere outside this book even though it is such a well known book and the notation has obvious advantages. does anyone else use in their daily lives?
 
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What is Spivak's notation?
 


As long as you know that \frac{\partial}{\partial x^i} depends on all the coordinates x^1,...,x^n and not just on x^i, using this notation is okay.
 


cristo said:
What is Spivak's notation?

He uses D1f(x,y,z) to denote the first partial derivative of f.
So far example you can write D1f(g(x,y),h(x,y)) = D1f(g(x,y),h(x,y))*D1g(x,y) + D2f(g(x,y),h(x,y))*D1h(x,y)
Whereas in classical notation it would be f(g(x.y),h(x.y)) = f(u.v) where u and v are functions of x any y and this gives us \frac{\partial{f}}{\partial{x}} = \frac{\partial{f}}{\partial{u}}}\frac{\partial{u}}{\partial{x}} + \frac{\partial{f}}{\partial{v}}}\frac{\partial{v}}{\partial{x}}
but f means two different things on the two sides of the equation

it is also very helpful if you have something like f(g(x,y) + h(h,y), k(x,y))
 

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