       Re: Contour integral around z_infinity != negative around origin

• To: mathgroup at smc.vnet.net
• Subject: [mg106616] Re: Contour integral around z_infinity != negative around origin
• From: dh <dh at metrohm.com>
• Date: Mon, 18 Jan 2010 05:39:50 -0500 (EST)
• References: <hiuuq0\$90e\$1@smc.vnet.net>

```
Hi Vince,

the question is if there are poles somewhere (inlcusive infinity,

assuming there are no essential singularities). If not the intergral is

always zero and the sign does not matter.

Maybe you remember the transformation x->1/x that changes the

orientation of the contour and thereby the sign.

Daniel

Vince Virgilio wrote:

> If I recall grad school correctly, the contour integral of f around

> z_infinity is not simply the negative of the contour integral of f

> around the origin. I never understood why not. I don't think I could

> pose the question to Mathematica properly, anytime soon. So I thought

> I'd bring it to this list. Would someone formulate these two contour

> integrals as Mathematica expressions, and attempt to draw an equality

> between the two? I'd be curious to see how Mathematica takes it.

>

> If this is nonsense, just leave it in wonderland.

>

> Thanks,

>

> Vince Virgilio

>

```

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