Top Posts
Recent comments
 Peter Cameron on New web address
 Peter Cameron on New web address
 dockie73 on New web address
 AMBAT VIJAYAKUMAR on George F. Simmons
 For DeepArcher « Log24 on George F. Simmons
Blogroll
 Astronomy Picture of the Day
 Azimuth
 British Combinatorial Committee
 Comfortably numbered
 Diamond Geezer
 Exploring East London
 From hill to sea
 Gödel's lost letter and P=NP
 Gil Kalai
 Jane's London
 Jon Awbrey
 Kourovka Notebook
 LMS blogs page
 Log24
 London Algebra Colloquium
 London Reconnections
 MathBlogging
 Micromath
 Neill Cameron
 neverendingbooks
 Noncommutative geometry
 numericana hall of fame
 Ratio bound
 Robert A. Wilson's blog
 Since it is not …
 Spitalfields life
 Sylvy's mathsy blog
 SymOmega
 Terry Tao
 The Aperiodical
 The De Morgan Journal
 The ICA
 The London column
 The Lumber Room
 The matroid union
 Theorem of the day
 Tim Gowers
 XKCD
Find me on the web

Join 664 other subscribers
Cameron Counts: RSS feeds
Meta
Tag Archives: Pablo Spiga
The road closure property
My work with João Araújo and other semigroup theorists has produced a number of permutation group properties which lie between primitivity and 2homogeneity, especially the synchronization family. Another of these is the road closure propery, which I have discussed here … Continue reading
The Hall–Paige conjecture
A Latin square of ordern is an n×n array of symbols from an alphabet of size n with the property that each symbol in the alphabet occurs once in each row or column. Two Latin squares L and M are … Continue reading
Synchronization update
There is some recent news about the synchronization project. Two steps forward have occurred. The setup Here is a brief recapitulation. Let G be a transitive permutation group on Ω, where Ω = n. We say that G is nonsynchronizing if there … Continue reading
Summer school at Marienheide
Last week, I was lecturing at a summer school in Franz Dohrmann Haus, a very pleasant conference centre in the small town of Marienheide, not far from Köln. Apart from a walk on Wednesday afternoon, I didn’t get much exercise, … Continue reading
Posted in events
Tagged Cheryl Praeger, Csaba Schneider, O'NanScott theorem, Pablo Spiga, permutation groups
Leave a comment
Two publications
I don’t think it happened to me before that two of my papers were “published” on the same day. Fortunately, it didn’t happen on April Fools’ Day … One is my paper with Pablo Spiga on switching classes. I described … Continue reading
Primitive switching classes
Last year I wrote here about switching classes of graphs for which the switching class has a primitive automorphism group. (I repeat the definitions briefly below.) I conjectured that, except for the trivial switching classes of the complete and null … Continue reading
Posted in exposition, mathematics
Tagged Akos Seress, Don Taylor, Pablo Spiga, primitive group, switching class, twograph
Leave a comment
Automorphism groups of hypergraphs
I am getting old and forgetful, but I don’t think I said anything here about this problem yet. If I did, apologies for the repetition – but there is something new to report! In April, Laci Babai and I finally … Continue reading
Posted in exposition, mathematics
Tagged Akos Seress, hypergraphs, Laci Babai, Pablo Spiga, primitive groups
Leave a comment