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BEGIN:VEVENT
SUMMARY:Mel Nathanson (CUNY)
DTSTART:20260910T190000Z
DTEND:20260910T200000Z
DTSTAMP:20260906T193938Z
UID:NYNTS/1
DESCRIPTION:Title: <a href="https://researchseminars.org/talk/NYNTS/1/">Si
 don sets with Delta-separated sumsets</a>\nby Mel Nathanson (CUNY) as part
  of New York Number Theory Seminar\n\n\nAbstract\nThe set $A$ is a $B_h$-s
 et if every element of the sumset $hA$ has a unique representation as a su
 m of $h$ elements of $A$.  A $B_2$-set is also called a Sidon set.  A $B_{
 h\,\\Delta}$-set is a $B_h$-set $A$ whose sumset $hA$ is $\\Delta$-separat
 ed\, that is\, \n$x'-x \\geq \\Delta$ for all $x\,x' \\in hA$ with $x < x'
 $.\nUpper and lower bounds are obtained for the cardinality of the largest
  $B_{2\,\\Delta}$-sets contained in   $\\{1\,2\,\\ldots\, n\\}$\, that is\
 , sets $A \\subseteq \\{1\,2\,\\ldots\, n\\}$ such that\, if $a\,b\,c\,d \
 \in A$ and $\\{a\,b\\} \\neq \\{c\,d\\}$\, then $|(a+b)-(c+d)| \\geq \\Del
 ta$.\n
LOCATION:https://researchseminars.org/talk/NYNTS/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mel Nathanson (CUNY)
DTSTART:20260917T190000Z
DTEND:20260917T200000Z
DTSTAMP:20260906T193938Z
UID:NYNTS/2
DESCRIPTION:Title: <a href="https://researchseminars.org/talk/NYNTS/2/">B_
 h-sets and perturbations in normed vector spaces</a>\nby Mel Nathanson (CU
 NY) as part of New York Number Theory Seminar\n\n\nAbstract\nThe subset $A
  = \\{a_i:i \\in I\\}$ of a normed vector space is a $B_h$-set if every el
 ement \nof the sumset $hA$ has a unique representation as a sum of $h$ ele
 ments of $A$.  \nAn $\\varepsilon$-perturbation of $A$ is a set $A' = \\{a
 '_i:i\\in I\\}$ such that $|a'-a|<\\varepsilon$ \nfor all $i \\in I$. \nLe
 t $\\Delta_{hA} = \\inf\\{|x'-x| : x\,x' \\in hA \\text{ and } x\\neq x'\\
 }$.  \nIt is proved that if $A$ is  finite or countably infinite set with 
 $\\Delta_{hA}>0$\, \nthen there is a $B_h$-set $A'$ that is an $\\varepsil
 on$-perturbation of $A$.\n
LOCATION:https://researchseminars.org/talk/NYNTS/2/
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