What is a shadow generating function?

Question

anonymous · Answer

shadow of what?

anonymous · Answer

and on what?

anonymous · Answer

Sounds like you're describing vector projection...

asnaseer · Answer

look at page 4 of: https://docs.google.com/viewer?a=v&q=cache:S9HzZ1KFxpwJ:cdn.transtutors.com/UploadAssignments/63970_1_Port-2012-2013.pdf+%22shadow+generating+function%22&hl=en&gl=uk&pid=bl&srcid=ADGEESgBRzexa6AQ4HpFfUZDq96fA-sldRfp19EtYCwv2G0BOVsokvRW4vu3LDrGqweonXyQts6RtRIaOip9uPvkugcLdBJKsJQUYBzHdljNjl7K8gPmLI87k1EJP9A6Uh-BJeCMnqjA&sig=AHIEtbQKuUaj27361pETt4V2eL9pZhgv-w

anonymous · Answer

Oh wow... interesting. Never heard of that.

asnaseer · Answer

Basically it states:

A "shadow function" to $y_1$ is another quadratic $y_2$ which shares the same vertex as $y_1$. However $y_2$ has opposite concavity to $y_1$ and its zeros are in the form $a\pm b$.

anonymous · Answer

That document is exactly what i'm working from... the question i'm referring to is "Hence, or otherwise, express y2 in terms of y1 and ym , where ym is called the “shadow
generating function”." But I don't know how to get ym if i don't know what a shadow generating function is.