# gst: approaching the automorphism groupoid of a groupoid

AA << construct two groupoids from morphisms of groupoids, with one from a categorical viewpoint and the other from a geometric viewpoint. (AA) show that for each pair of groupoids, the two kinds of groupoids of morphisms are equivalent. Then (AA) study the automorphism groupoid of a groupoid. >>

Bohui Chen, Cheng-YongDu, et al. The groupoid structure of groupoid morphisms. J of Geometry and Physics Vol 145 doi: 10.1016/j.geomphys.2019.103486  Aug 12,  2019.     https://www.sciencedirect.com/science/article/pii/S0393044019301676

Also

"groupoid" in: https://en.m.wikipedia.org/wiki/Groupoid  

# game: mutual cooperation without non-cooperative actions

AA << have developed a model that consists of all possible strategies using a one-period memory of past actions. This model enables us to analyze a "melting pot" of strategies, wherein several strategies interact and compete with each other. (AA) results revealed that one strategy, in which one escapes if a partner defects or cooperates if a partner becomes a loner, dominates and maintains cooperation in an alternating prisoner's dilemma game. >>

H. Yamamoto, I. Okada, et al.
Effect of voluntary participation on an alternating and a simultaneous prisoner's dilemma.  Phys. Rev. E 100, 032304 Sep 11,  2019.    https://journals.aps.org/pre/abstract/10.1103/PhysRevE.100.032304   

The Prisoner's Dilemma: Exploring a strategy that leads to mutual cooperation without non-cooperative actions. Rissho University. Sep 23, 2019.   https://m.phys.org/news/2019-09-prisoner-dilemma-exploring-strategy-mutual.html   

Also

keyword "game" in "FonT"   https://flashontrack.blogspot.com/search?q=game

# life: the generation of multiple bubbles mediated by gerrymandering could self trapped in deadlock

AA << analysis provides an account of the vulnerabilities of collective decision-making to systematic distortion by restricted information flow. >>

The analysis << also highlights a group-level social dilemma: information gerrymandering can enable one party to sway decisions in its favour, but when multiple parties engage in gerrymandering the group loses its ability to reach consensus and remains trapped in deadlock. >>

Alexander J. Stewart, Mohsen Mosleh, et al. Information gerrymandering and undemocratic decisions. Nature. volume 573, pages 117–121 Sep 4,  2019.     https://www.nature.com/articles/s41586-019-1507-6    

Alexander J. Stewart, Joshua B. Plotkin. Here’s what happens when political bubbles collide. Sep 4, 2019.     https://theconversation.com/heres-what-happens-when-political-bubbles-collide-121856  

Also

keyword "bubble" in: FonT  https://flashontrack.blogspot.com/search?q=bubble

Also

<< dell' ombre a bolle di neurodiscoide di ghiozzo >> in: 1813b - alea in psichedelico catino.  https://inkpi.blogspot.com/2005/03/1813b-alea-in-psichedelico-catino.html

# gst: apropos of weak bonds, hydrophobic cohesion to stabilize the double helix of DNA

<< The main stabilizer of the DNA double helix is not the base-pair hydrogen bonds but coin-pile stacking of base pairs, whose hydrophobic cohesion, requiring abundant water, indirectly makes the DNA interior dry so that hydrogen bonds can exert full recognition power. (..) (AA) speculate that hydrophobic catalysis is a general phenomenon in DNA enzymes. >>

<< The forces that stabilize the DNA double helix are a prerequisite for the secure storage of genetic information but their modest strength is also necessary for the efficient processes of replication, transcription, recombination, and repair systems-wherein thermal fluctuations, or "breathing," play an important role >>

Bobo Feng, Robert P. Sosa, et al. Hydrophobic catalysis and a potential biological role of DNA unstacking induced by environment effects. PNAS.  116 (35) 17169-17174; Aug 27, 2019.  doi: 10.1073/ pnas.1909122116.    https://www.pnas.org/content/116/35/17169

DNA is held together by hydrophobic forces. Chalmers University of Technology. Sep 23, 2019.     https://m.phys.org/news/2019-09-dna-held-hydrophobic.html   

# gst: the hypothesis of a first order phase transition (a type of abrupt phase transition) to originate black holes observed by LIGO/Virgo in binary mergers.

<<  To summarize, motivated by the ~10 M* (mass similar to that of the sun) black holes observed by LIGO/Virgo in binary mergers, (AA) entertained the possibility that the quark-gluon confinement phase transition was first order due to the effect of 6 light quarks. The larger number of light quarks, compared to the standard case, pushes the transition temperature below ∼100 MeV. The first order nature of the transition significantly improves the likelihood of forming primordial black holes and its lower temperature suggests that these black holes can potentially be as heavy as ∼10 M*, compared to ∼M* for the standard QCD transition. >>

Hooman Davoudiasl.  LIGO/Virgo Black Holes from a First Order Quark Confinement Phase Transition. Phys. Rev. Lett. 123, 101102. Sep 6, 2019.   https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.123.101102  

Ingrid Fadelli. Theory proposes that LIGO/Virgo black holes originate from a first order phase transition. Sep 23, 2019.    https://m.phys.org/news/2019-09-theory-ligovirgo-black-holes-phase.html  

QCD = quantum chromodynamic  
https://en.m.wikipedia.org/wiki/Standard_Model

# gst: dealing with bistability (through hyperbolic paraboloid origami)

<< Origami offers an avenue to program three-dimensional shapes via scale-independent and non-destructive fabrication. >>

Using theoretical model, << which connects geometry to mechanics, (AA) prove that a folded hypar origami exhibits bistability between two symmetric configurations. Further, (AA) tessellate the hypar origami and harness its bistability to encode multi-stable metasurfaces with programmable non-Euclidean geometries. >>

Ke Liu, Tomohiro Tachi, Glaucio H. Paulino. Invariant and smooth limit of discrete geometry folded from bistable origami leading to multistable metasurfaces. Nature Comm. volume 10, Article number: 4238, 17 Sep 17, 2019.    https://www.nature.com/articles/s41467-019-11935-x  

Josh Brown. Hyperbolic paraboloid origami harnesses bistability to enable new applications. Georgia Institute of Technology. Sep 17, 2019.    https://m.techxplore.com/news/2019-09-hyperbolic-paraboloid-origami-harnesses-bistability.html 

# astro: test the 'no-hair' hypothesis on coalescent black holes (at the ~ 10% or ~ 20% levels)

<< Agreement between the postinspiral measurements of mass and spin and those using the full waveform supports the hypothesis that the GW150914 merger produced a Kerr black hole, as predicted by general relativity, and provides a test of the no-hair theorem at the ∼10% level. An independent measurement of the frequency of the first overtone yields agreement with the no-hair hypothesis at the ∼20% level.  >>

Maximiliano Isi, Matthew Giesler, et al. Testing the No-Hair Theorem with GW150914. Phys. Rev. Lett. 123, 111102. Sep 12, 2019.    https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.123.111102

Synopsis: Hunting for Hair on Coalescing Black Holes. A fresh look at data from the first detected black-hole merger supports the “no hair” theorem.  Sep 12, 2019.   https://physics.aps.org/synopsis-for/10.1103/PhysRevLett.123.111102

'No-hair' theorem   https://en.m.wikipedia.org/wiki/No-hair_theorem

Kerr black hole   https://en.m.wikipedia.org/wiki/Rotating_black_hole