Software, groups,
and combinatorics.
I'm Guido, a software developer and independent researcher in Vienna. I build open source tools and study how to arrange people into groups without repeating pairs.
More about meResearch
Research overview-
Parallel-Class Splitting and Constructive Lower Bounds for the Social Golfer Problem
Guido Witt-Dörring · Preprint · September 2026
Constructions from resolvable designs, including parallel-class splitting, together with explicit schedules that establish lower bounds for several parameter pairs.
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A Constructive Frontier for the Social Golfer Problem
Guido Witt-Dörring · Preprint · September 2026
A table of constructive lower bounds for every pair of group counts and sizes from 2 to 50, with 1,225 complete schedules and 33 improvements over cited published lower bounds.
Selected software
- GroupMixer
A web app for distributing people into balanced groups.
- VBA-StringTools
Unicode string handling for VBA on Windows and Mac.
- immich-admintools
Job monitoring and administrative tools for Immich.