New estimations for the Berezin number inequality

In this paper, by the definition of Berezin number, we present some inequalities involving the operator geometric mean. For instance, it is shown that if X, Y, Z∈ L(H) X,Y,Z∈L(H) such that X and Y are positive operators, then $${aligned} berʳ ( ( X{} Y ) Z ) &≤ ber ({ ( ZYZ ) rq/2}{q}+ {Xrp/2}{p} ) -1/pinfλ ∈ ( [ {X} ( λ ) ] rp/4- [ { ( ZYZ ) } ( λ ) ] rq/4 ) ², {aligned}$$ berr((X♯Y)Z)≤ber((Z⋆YZ)rq2q+Xrp2p)−1pinfλ∈Ω([X˜(λ)]rp4−[(Z⋆YZ)˜(λ)]rq4)2, in which $X{} Y=X1/2 ( X-1/2YX- 1/2 ) 1/2X1/2$ X♯Y=X12(X−12YX−12)12X12 , $p≥ q>1$ p≥q>1 such that $r≥ 2/q$ r≥2q and $1/p+1/q=1$ 1p+1q=1 .