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Aug 14, 2023 at 1:58 comment added japalmer So the new conjecture is that it holds with the additional condition that $g^{(3)}(x) \ge 0$ for $x > 0$.
Aug 14, 2023 at 1:38 comment added japalmer Yes, I checked it by inverting the convex function. It's strange because I'm pretty sure I can prove that if $g$ is concave or convex and $a(\phi)$ is montonic, then $b(\theta) = \int_0^{\pi/2} a(\phi) p(\phi;\theta) d\phi$ is monotonic. (reversed for concave $g$). I thought this was a stronger property given a theorem by Karlin on TP(3) kernels having that property, which is stronger than the SR(2) property, which is equivalent to the monotone likelihood ratio.
Aug 13, 2023 at 16:58 comment added Iosif Pinelis @japalmer : The "concave" part of your conjecture has now considered as well.
Aug 13, 2023 at 16:57 history edited Iosif Pinelis CC BY-SA 4.0
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Aug 13, 2023 at 16:51 vote accept japalmer
Aug 13, 2023 at 16:50 comment added japalmer I guess the inverse of that function also disproves the concave case. It must need a 3rd derivative condition.
Aug 13, 2023 at 16:27 comment added japalmer Wow, that's not good. I thought it applied in the convex case as well. But I'm pretty sure I can show that it holds for concave $g$. Do you have a counter-example for that too?
Aug 13, 2023 at 16:03 history answered Iosif Pinelis CC BY-SA 4.0