Biharmonic functions on groups and limit theorems for quasimorphisms along random walks

  title={Biharmonic functions on groups and limit theorems for quasimorphisms along random walks},
  author={Michael Bjorklund and Tobias Hartnick},
  journal={Geometry \& Topology},
MICHAEL BJORKLUND AND TOBIAS HARTNICK¨Abstract. We show for very general classes of measures on locally compact secondcountable groups that every Borel measurable quasimorphism is at bounded distancefrom a quasi-biharmonic one. This allows us to deduce non-degenerate central limit the-orems and laws of the iterated logarithm for such quasimorphisms along regular randomwalks on topological groups using classical martingale limit theorems of Billingsley andStout. For quasi-biharmonic… 
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