Let $a,b,c>0$ such that $a+b+c=1$ then we have : $$ a^{ab}c+b^{bc}a+c^{ca}b\leq 1-2abc\quad (1)$$
I have a proof :
By Bernoulli's inequality we have : $$a^{ab}c+b^{bc}a+c^{ca}b\leq (1+(a-1)ab)c+(1+(b-1)bc)a+(1+(c-1)ac)b=a+b+c+abc(a+b+c-3)=1-2abc$$
I was thinking for an alternative proof considering by example Young's inequality or someting like that .
Question :
Have you an alternative proof for $(1)$ ?
Thanks in advance !
Regards Max.