View Proposal #506

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ID506
First NameJoshua
Last NameZelinsky
InstitutionISU
Speaker Categoryfaculty
Title of TalkLower and upper bounds in integer complexity.
AbstractDefine ||n|| to be the complexity of n, the smallest number of 1's needed to write n using an arbitrary combination of addition and multiplication. John Selfridge showed that ||n|| is at least 3log3n for all n, and this lower bound is obtained exactly when n is a power of 3. Richard Guy noted the trivial upper bound of 3log_2 n for all n bigger than 1, by writing n in base 2. This talk will discuss work improving the upper bound, as well as work leading to a complete classification of numbers whose complexity is close to the lower bound. Along the way, we'll develop connections to both ordinal numbers and the p-adics.
Subject area(s)Number theory
Suitable for undergraduates?Y
Day PreferenceSaturdayStrong
Computer Needed?Y
Bringing a laptop?N
Overhead Needed?N
Software requests
Special Needs
Date Submitted09/17/2018
Year2018