10 papers
A tight bound for affine-linearity, via universal ballot matrices
Apoorva Khare, Ashwin Sah
Based on work with Greenfeld and with Ziegler, Tao showed a concatenation result that if a map is affine-linear on every line parallel to the coor…
The entrywise calculus and dimension-free positivity preservers, with an Appendix on sphere packings
Apoorva Khare
We present an overview of a classical theme in analysis and matrix positivity: the question of which functions preserve positive semidefiniteness when applied entrywise. In additio…
Majorization via positivity of Jack and Macdonald polynomial differences
Hong Chen, Apoorva Khare, Siddhartha Sahi
Majorization inequalities have a long history, going back to Maclaurin and Newton. They were recently studied for several families of symmetric functions, including by Cuttler--Gre…
Maps preserving the sum-to-difference ratio
Sunil Chebolu, Apoorva Khare, Anindya Sen
For a field , what are all functions that satisfy the functional equation $f \left( (x+y)/(x-y) \right) = (f(x) + f(y))/(f(…
Numerical radius and operator norm of Kronecker products and Schur powers: inequalities and equalities
Pintu Bhunia, Sujit Sakharam Damase, Apoorva Khare
Suppose is a complex matrix and is a bounded linear operator on a complex Hilbert space $\mat…
Log-concavity of characters of parabolic Verma modules, and of restricted Kostant partition functions
Apoorva Khare, Jacob P. Matherne, Avery St. Dizier
In 2022, Huh-Matherne-Mészáros-St. Dizier showed that normalized Schur polynomials are Lorentzian, thereby yielding their continuous (resp. discrete) log-concavity on the positiv…