Welcome! The CMSA seminar aims to bring together combinatorialists of Australasia and the world. It is started during the COVID-19 lockdown days, and may continue afterwards. We plan to hold the seminar roughly every two weeks on Wednesday, starting on the 20th of May.

Subscribe: Email cmsa-webinar AT monash.edu with the subject "subscribe". We send announcements and zoom details before every talk.

Organisers: Anita Liebenau and Nina Kamčev. Please email us with your feedback and suggestions.

We will mainly be using one of the following two time slots, conversion to your time zone is available via the links:
11am AEST, 9pm ET or 5pm AEST, 9am CET .

Date (AEST)SpeakerTitle Video
20 May '20, 11am Brendan McKay A scientist's adventure into pseudoscience: the strange case of the Bible Codes Zoom
3 June '20, 4pm John Bamberg Vanishing Krein Parameters in Finite Geometry
17 June '20, 5pm Fiona Skerman Branching processes with merges and locality of hypercube’s critical percolation
1 July '20, 5pm Tibor Szabó tbc
15 July '20, 11am Daniel Horsley tbc
29 July '20, 5pm Annika Heckel tbc

17 June 2020, 5pm AEST Fiona Skerman (Uppsala University)
Branching processes with merges and locality of hypercube’s critical percolation
Abstract: We define a branching process to understand the locality or otherwise of the critical percolation in the hypercube; that is, whether the local structure of the hypercube can explain the critical percolation as a function of the dimension of the hypercube.
The branching process mimics the local behaviour of an exploration of a percolated hypercube; it is defined recursively as follows. Start with a single individual in generation 0. On an first stage, each individual has independent Poisson offspring with mean (1+p)(1-q)k where k depends on the ancestry of the individual; on the merger stage, each pair of cousins merges with probability q.
We exhibit evidence of a critical merger probability qc=qc(p) for extinction of the branching process. When p is sufficiently small, the first order terms of qc coincide with those of the critical percolation for the hypercube, suggesting that percolation in the hypercube is dictated by its local structure. This is work in progress with Laura Eslava and Sarah Penington.

3 June 2020, 4pm AEST John Bamberg (University of Western Australia)
Vanishing Krein Parameters in Finite Geometry
Abstract: The Krein condition on the parameters of a strongly regular graph (L. L. Scott 1973, 1977) is one of the most successful tools in ruling out sets of possible parameters of strongly regular graphs. Delsarte’s generalisation for association schemes (1973) has also played an important role in the theory of association schemes and its applications: to coding theory, design theory, and finite geometry. In this talk, we give a brief introduction to the interplay between association schemes and finite geometry, and some recent results on vanishing Krein parameters of the speaker and his student Jesse Lansdown.

20 May 2020, 11am AEST Brendan McKay (Australian National University)
A scientist's adventure into pseudoscience: the strange case of the Bible Codes
Abstract: Over the centuries, many claims have been made of numerical patterns of miraculous nature hidden within the text of sacred writings, including the Jewish, Christian and Islamic scriptures. Usually the patterns involve counting of letters and words, or calculations involving numerical equivalents of the letters.
Until recently, all such claims were made by people with little mathematical understanding and were easily explained. This situation changed when a highly respected Israeli mathematician Eliyahu Rips and two others published a paper in the academic journal Statistical Science claiming to prove that information about medieval Jewish rabbis was encoded in the Hebrew text of the Book of Genesis. The journal reported that its reviewers were "baffled".
The paper in Statistical Science spawned a huge "Bible Codes" industry, complete with best selling books, TV documentaries, and even an adventure movie.
The talk will reveal the inside story of the Codes and the people behind them, from their inception through to their refutation.