\int dz G[z,y]^n J[z] [/itex] vs. (\int dz G[z,y] J[z])^n

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In summary, the conversation discusses the possibility of an explicit transformation that could be constructed to give either one of two integrals from the other. However, it is believed that such a transformation is not possible in all generality, as it is not difficult to come up with specific G and J functions that make one integral divergent and the other well defined. However, there may be a possibility for such a transformation for restricted classes of G and J functions.
  • #1
wandering.the.cosmos
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If one is given two known functions G[x,y] and J[y], is there an explicit transformation that could be constructed to give us either one of the following integrals from the other?

[tex] \int dz G[z,y]^n J[z] [/itex]
[tex] \left( \int dz G[z,y] J[z] \right)^n [/itex]

Here n is an integer.

Thanks!
 
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  • #2
Ahh made tex won't work in titles, better name it integrals or something. I would imagine that transformation is not possible, but I don't know.
 
  • #3
I would imagine not because it's not too hard to come up with G and J which give your first integral as divergent over particular domains for certain n and your second one well defined.
 
  • #4
AlphaNumeric said:
I would imagine not because it's not too hard to come up with G and J which give your first integral as divergent over particular domains for certain n and your second one well defined.

This means the transformation doesn't exist in all generality. But I'd be interested in such a transformation even for restricted classes of G and J.
 

1. What is the difference between \int dz G[z,y]^n J[z] and (\int dz G[z,y] J[z])^n?

The main difference between these two expressions is the order of operations. In the first expression, the function G[z,y] is raised to the power of n before being integrated over z. In the second expression, the integration over z is performed first, and the resulting value is then raised to the power of n.

2. Can these two expressions be interchanged?

No, these two expressions cannot be interchanged as they have different mathematical properties. The first expression is known as a power series and the second expression is known as a power function.

3. How do these expressions relate to each other?

These expressions are related by the mathematical identity known as the binomial theorem. This theorem states that (a+b)^n = \sum_{k=0}^{n} \binom{n}{k} a^{n-k} b^k, which can be applied to the second expression to show its equivalence to the first expression.

4. What are the practical applications of these expressions in science?

These expressions are commonly used in statistical mechanics and quantum mechanics to calculate partition functions and expectation values. They are also used in various other fields of physics, such as electromagnetism and thermodynamics, to calculate various quantities.

5. How do these expressions relate to the concept of integration by parts?

The first expression is an example of integration by parts, where the function J[z] is integrated while G[z,y] is differentiated n times. The second expression is the result of applying integration by parts n times, resulting in a repeated integral of G[z,y].

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