The paper deals with the following Kirchhoff‐type problem
M()∬ℝ2N1pfalse(x,yfalse)false|vfalse(xfalse)−vfalse(yfalse)false|pfalse(x,yfalse)false|x−yfalse|N+pfalse(x,yfalse)sfalse(x,yfalse)dxdyfalse(−normalΔfalse)pfalse(·false)sfalse(·false)vfalse(xfalse)=μgfalse(x,vfalse)+false|vfalse|rfalse(xfalse)−2vin0.1em0.1emnormalΩ,v=0in0.1em0.1emℝN\normalΩ,
where M models a Kirchhoff coefficient,
false(−normalΔfalse)pfalse(·false)sfalse(·false) is a variable s(·)‐order p(·)‐fractional Laplace operator, with
sfalse(·false):ℝ2N→false(0,1false) and
pfalse(·false):ℝ2N→false(1,∞false). Here,
normalΩ⊂ℝN is a bounded smooth domain with N > p(x, y)s(x, y) for any
false(x,yfalse)∈truenormalΩ¯×truenormalΩ¯, μ is a positive parameter, g is a continuous and subcritical function, while variable exponent r(x) could be close to the critical exponent
ps∗false(xfalse)=Ntruep¯false(xfalse)false/false(N−trues¯false(xfalse)truep¯false(xfalse)false), given with
truep¯false(xfalse)=pfalse(x,xfalse) and
trues¯false(xfalse)=sfalse(x,xfalse) for
x∈truenormalΩ¯. We prove the existence and asymptotic behavior of at least one non‐trivial solution. For this, we exploit a suitable tricky step analysis of the critical mountain pass level, combined with a Brézis and Lieb‐type lemma for fractional Sobolev spaces with variable order and variable exponent.