Kalpa: Josephus

31 January

Kalpa Madhava
Josephus Problem

Mohammad: Time

29 Nov 2018

Mohammad Sayeh
Time and Freedom

Cancelled due to external factors....

Lakshika: quadratic forms

Pythagorean triples, Wikipedia

1 and 8 Nov 2018

Lakshika Gunawardana 
Quadratic forms and representations
Part 1 1nd 2



Here are some universal forms from Lakshika (click to display).

(Recall that the quadruple in bold letters turned out to be false)




And here is the Plimpton 322 with Pythagorean triples.  Written about 1800 BCE.

John: sequential covering designs

18 and 25 October

John McSorley
What is a sequential covering design?  Come and find out...

Part 1 and 2

Quaternions: 175th anniversary

175th anniversary

of discovery^* of quaternions 

i² = j² = k² = -1

16 October 1843

Brougham Bridge, Dublin

William Rowan Hamilton

We celebrated appropriately the event by consuming a large amount of pizza prepared for us by Quatros

(Nomen-omen -- as noticed by Mohammad S.)

*) If you think "discovery" should be replaced by "invention" or else  -- please feel free to argue in the comments section.

After party...

Kalpa: rolling balls

From pages of J. Baez 

27 Sep and 4 , 11 Oct 2018

Kalpa Madhawa
Octonions and the rolling ball 

(Three parts)



Extra materials
Books suggested by Kalpa:

• Travian Dray:  The Geometry of the Octonions 
• John Hortan Convey:  On Quaternions and Octonions 

See also the paper and the video

• J. Baez and J. Huerta: G2 and the rolling balls 
• J. Baez: Lecture on Youtube

And here are suggestions from Terry-Ann:

• Youtube: on Octonions
• brief video of her stating that Octonions relate to particle physics, (without much explanation)

Shajesh: topological insulators

From Wikipedia

6 , 13, 20 September, 2018 

K.V. Shajesh  (Physics)  
Towards understanding topological insulators in a classical setting 

1. Lagrangian
2. Boundary conditions
3. Optical properties

2017

11 Oct  2017 
Mohammad Sayeh
The residue number system and applications

2017 SPRING 

4 May 2017
Jerzy Kocik
From circles to gears and back again 
-- on Stern-Brocot trees, Apollonian crowns, and related wonders 
(with Zeta function in the background).

27 Apr 2017
Shajesh Kuloth
Divergence theorem across delta-functions

13, 19 Apr 2017
Zeid Ghalyoun
A Primer on Eisenstein Series (two parts)

30 Mar, 6 Apr 2017
Mohammad Sayeh
Optimization with Collective Neurons 
(see also Hopfield's ealy work: 1982Hopfield ,  1984Hopfield, 1985Hopfield, 1986Hopfield .

23 Feb and 3, 8, 22 Mar 2017
Borzu Toloui
Game Theory and Quantum Mechanics: Deriving the Born Rule (4 parts)
Below are the links for the references once again. 

• Deutsch's original paper of 1999:  https://arxiv.org/pdf/quant-ph/9906015.pdf
• A more extensive study of the decision theoretic result and its philosophical implications: https://arxiv.org/pdf/quant-ph/0211104.pdf
• The constructor theory version of it that incorporates the result in the new approach to physics that is being developed: https://arxiv.org/pdf/1507.03287.pdf
• On the problem of testing physical theories, especially different versions of quantum theory: https://arxiv.org/pdf/1508.02048.pdf
• And finally, here are a set of video lectures by Deutsch on quantum mechanics and quantum computing: http://www.quiprocone.org/Protected/DD_lectures.htm
• On You Tube (lower quality):  https://www.youtube.com/playlist?list=PL4cl2VeMbE330GKLkYIE8UBrrYdp8L9mR

2, 9, 15 Feb 2017
John Mcsorley
Gentle introduction to Game Theory (3 parts)

26 Jan 2017
Jerzy Kocik
Chebyshev, Lucas and Fibonacci polynomials by matrices

19 Jan 2017
Just coffee and gossip

2016

Started a new seminar AG&RA
which eventually merged its name
with the name of the previous series of Potpourri Seminar

2016 FALL

8 Dec 2016
Jerzy Kocik
Evaluations graphs motivated by groups SU(2) and SL(2).

1 Dec 2016
T. Kalpa Madhawa
Octonions -- an introduction

Nov 16
Borzu Toloui
Numbers as games - an introduction
See also: http://web.mit.edu/sp.268/www/2010/surreal.pdf
John McSorley suggested  https://en.wikipedia.org/wiki/Nimber

Nov 2, 10
Borzu Toloui
Conversation on surreal numbers

Oct 20, 27
Jerzy Kocik
Connections of SL(2,R) with other phenomena in earth and heaven
(two parts)

Oct 6, 13, 2016
Mohammad. Sayeh
Time  (+ free discussion)
(two parts)

22, 29 Sep 2016
Borzumehr Toloui 
Fibonacci Anyons

8, 15 Sep 2016
Philip Feinsilver
Fibonacci now!

1 Sep 2016
Chat on the news in math, physics, 
astrology, alchemy and other sciences.

2016 SPRING

7 Apr 2016

K. V. Shajesh
1+2+3+...=-1/12: Casimir energy in 1+1 dimensions

31 March 2016
Philip Feinsilver
Fibonnaci meets Krawtchouk

11, 18, 25 (?)Feb 2016
Rodrigo Carraminiana
Finite fields/rings and finite geometries
(three parts)

2015

The list below is incomplete.  Please send info on things missed.

SPRING

30 Mar, 2 Apr 2015
Kamal Adhikari
Realizing a NSF with four band Templates
(two parts)

26 Feb
Kamal Adhikari
Realizations of Smale flows using  templates

12, 19 Feb 2015
Alan Smith
Twin primes conjecture
(two parts)

29 Jan, 5 Feb  2015  (1pm)
Jerzy Kocik
A novel geometric construction relevant for relativity theory
(two parts)

2014

Potpourri Seminar is revived.
The list below is incomplete.  Please send info on things missed.


Nov 13 2014          (1pm)
Ethan Lightfoot
Apollonian disk packing and number theory

27 Feb 2014
Jerzy Kocik
Representations of SU(2) -- math 101

13 Feb 2014 (3pm)
Jerzy Kocik
Spin Networks From Tensor Graphical Calculus

2007

Needs to be completed  (Help!)


1, 8 March 2007
Om Agrawal
Fractional Derivatives and their Applications

22 Feb 2007
Philip Feinsilver 
Addition formula for generalized tangents

1, 8, 15 Feb 2007
Jerzy Kocik
Underground Integer Sequences and Spinors

25 Jan 2007
Jerzy Kocik
Integer Lens Sequences and Classification of "Puzzles"