24 citations · 80 across the 39 of their papers we have counts for
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math.FA2009★ 4 cited
Weighted shifts on directed trees
Zenon Jablonski, Il Bong Jung, Jan Stochel
A new class of (not necessarily bounded) operators related to (mainly infinite) directed trees is introduced and investigated. Operators in question are to be considered as a gener…
math.FA2009
Extending positive definiteness
D. Cichoń, J. Stochel, F. H. Szafraniec
The main result of the paper gives criteria for extendibility of sesquilinear form-valued mappings defined on symmetric subsets of *-semigroups to positive definite ones. By specif…