Talk:Sigmoid function

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Call me crazy, but since when is the Hyperbolic_cosine considered "S shaped"? If this is a typo, I'm not sure what other function it was supposed to be. --65.147.0.105 15:25, 28 May 2004 (UTC)

• Right you are, I don't know what I was thinking. Fixed. (The error function is a proper sigmoid, right?)
  Jorge Stolfi 10:24, 31 May 2004 (UTC)

[edit] Recent changes to this page

Isn't it better to redirect this page to the logistic function page? Or restore this page to its former glory? The current page is kinda pathetic.

[edit] local extrema?

Do you really mean "local minimum" and "local maximum"? The example function given clearly doesn't have any local minima or maxima (but it does have a global minimum of 0 and a global maximum of 1) -- Somebody

Perhaps what is meant is that the second derivative (curvature) has a local minimum and maximum? BTW, I do not agree that the function has global extrema, because as I learned them and as the article on them states, they are points in the domain of the function and are always also local extrema. This function has none. The image of the function has supremum of 1 and infimum of 0, though (ie. the asymptotes of this function are y=0 and y=1). 82.103.198.180 10:03, 23 July 2006 (UTC)

Maybe it's for complex argument values? One is led to think of reals only because the plot is 2d, but maybe the text doesn't assume that. Coffee2theorems 18:22, 23 July 2006 (UTC)