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Jun 20, 2022 at 8:27 history edited Jojo CC BY-SA 4.0
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Jun 20, 2022 at 8:14 history edited Jojo CC BY-SA 4.0
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Jun 20, 2022 at 8:11 vote accept Jojo
Jun 20, 2022 at 7:52 history became hot network question
Jun 20, 2022 at 7:41 answer added Emil Jeřábek timeline score: 13
Jun 19, 2022 at 22:11 comment added LSpice @GeraldEdgar, such functions still have $h$ constant (take $a = 1$). Then the restriction is that $f$ is constant on powers (i.e., that $b \mapsto f(a^b)$ is constant for all $a$), and we may take $g = f$ and $h = 0$.
Jun 19, 2022 at 21:02 comment added Oliphaunt @Anixx thanks for that link, that seems very apropos. Also to the original poster at math.se.
Jun 19, 2022 at 19:40 comment added Gerald Edgar If we find that there is no non-trivial solution in reals, how about asking for maps $\mathbb N \to \mathbb N$ where $f(a^b) = g(a)+h(b)$.
Jun 19, 2022 at 19:32 history edited Jojo CC BY-SA 4.0
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Jun 19, 2022 at 19:30 review Close votes
Jun 24, 2022 at 3:01
Jun 19, 2022 at 19:12 comment added Emil Jeřábek It's not clear to me what is the intended domain of $a$ and $b$, as $a^b$ is not well defined for arbitrary real $a,b$. But anyway, the natural solution, which works for $a>1$ and $b>0$, is $\log\log a^b=\log\log a+\log b$.
Jun 19, 2022 at 19:06 answer added LSpice timeline score: 3
Jun 19, 2022 at 19:00 history edited LSpice CC BY-SA 4.0
`\eqref`
Jun 19, 2022 at 18:59 comment added LSpice It's clear to me that $a^b$ isn't symmetric in $a$ and $b$, but not that $f(a^b)$ isn't; and, indeed, the example of $f = 0$ shows that it can be. I guess more important is that $f(1^b)$ is constant.
Jun 19, 2022 at 18:54 comment added Anixx This may be relevant: en.wikipedia.org/wiki/…
Jun 19, 2022 at 18:47 history edited Jojo CC BY-SA 4.0
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Jun 19, 2022 at 18:38 history asked Jojo CC BY-SA 4.0