Difference between revisions of "Physical / geometric interpretation of complex integration"

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There are many geometric and physical interpretations of integrals of real-valued functions (such as are, volume, work etc.). However, a similar interpretation is rarely discussed for complex contour integral. The following interpretation of contour integration is due to Pólya (George Pólya and Gordon Latta, Complex Variables, Wiley, 1974.)
 
There are many geometric and physical interpretations of integrals of real-valued functions (such as are, volume, work etc.). However, a similar interpretation is rarely discussed for complex contour integral. The following interpretation of contour integration is due to Pólya (George Pólya and Gordon Latta, Complex Variables, Wiley, 1974.)
  
Let <math> \gamma </math> be a simple closed smooth curve in the complex plane, and <math> f </math> be a (complex-valued) function defined on <math> \gamma </math>. Parametrize <math> \gamma </math> with arc length <math> s </math>. As usual,  have <math> f(z) = u(z) + iv(z) </math>. Consider a vector field
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Let <math> \gamma </math> be a simple closed smooth curve in the complex plane, and <math> f </math> be a (complex-valued) function defined on <math> \gamma </math>. Parametrize <math> \gamma </math> with arc length <math> s </math>. As usual,  have <math> f(z) = u(z) + iv(z) = u(x,y) + iv(x,y)</math>. Consider a vector field <math> {\bf F} (x,y) = [u(x,y), -v(x,y)] </math>

Revision as of 10:59, 21 December 2021

There are many geometric and physical interpretations of integrals of real-valued functions (such as are, volume, work etc.). However, a similar interpretation is rarely discussed for complex contour integral. The following interpretation of contour integration is due to Pólya (George Pólya and Gordon Latta, Complex Variables, Wiley, 1974.)

Let [math]\displaystyle{ \gamma }[/math] be a simple closed smooth curve in the complex plane, and [math]\displaystyle{ f }[/math] be a (complex-valued) function defined on [math]\displaystyle{ \gamma }[/math]. Parametrize [math]\displaystyle{ \gamma }[/math] with arc length [math]\displaystyle{ s }[/math]. As usual, have [math]\displaystyle{ f(z) = u(z) + iv(z) = u(x,y) + iv(x,y) }[/math]. Consider a vector field [math]\displaystyle{ {\bf F} (x,y) = [u(x,y), -v(x,y)] }[/math]