## Last talk of the Online Seminar Series 2020 — V. M. Abrusci: Syllogism and linear logic

The last talk for the year within the cycle of online seminars organized by the Milan Logic Group will be given by Vito Michele Abrusci on December 3rd, 2020, at 10:30 via Zoom. Please contact us for details for joining and stay tuned to this website for upcoming news on events for 2021.

Abstract.

Discoveries on syllogisms, induced by linear logic, will be presented:

a)     Categorical Propositions and Syllogisms are closed under duality. The system of Aristotelian syllogisms (1st, 2nd and 3rdfigures) is complete under duality.

b)    Categorical Propositions and Syllogisms may be represented inside multiplicative fragment of Linear Logic (no need of contraction and weakening rules, no need of first order quantifiers). Better understanding of the Aristotelian notion of “contradictory propositions”.

c)     Syllogisms as proof-nets, and thus as geometrical objects and as programs.

d)    Why 1st figure syllogisms are simple syllogisms, and the other syllogisms are not simple? A geometrical answer: 1st figure syllogisms are planar proof-nets, whereas other syllogisms are not planar proof-nets.

e)    Reductions of syllogisms to 1st figure syllogisms are geometrical ways to transform non-planar graphs into planar graphs.

## Applied logic for… the United Nations

I am proud to announce my logical contribution to the “United Nations Convention against Transnational Organized Crime and the Protocols thereto ” (UNTOC), in particular concerning its Review Mechanism.

The Convention represents the only global treaty instrument to fight transnational organized crime, as it counts 190 States parties.

An important obligation for the parties to the Convention is the participation in a peer review mechanism, through which States review each other, on how they implemented the measures requested by the Convention (or its Protocols).

This means that, according to the relevant resolution, each State party should be assigned some reviewers in a random fashion,  subject to  a series of constraints, such as, for instance:

“ (a) States shall not undertake mutual reviews;

(b) For each instrument, a State party under review shall not be reviewed by States which are not parties to the same instrument; in the case that a drawn reviewing State is not party to all the instruments to which the State under review is party, an additional drawing of lots shall be carried out so as to select an additional reviewing State only for those instruments;

(c) The total number of reviewing States for all instruments shall not exceed four unless the State under review decides otherwise…. ”

I was involved at this point, in devising a fair, random procedure for the assignment of reviewers, complying with all the relevant constraints.

After realizing that, due to the intricacies of the requirements, a standard physical procedure, consisting in drawing of lots, would have requested a forbidding amount of time for preparation and material execution, we opted for an automated procedure.

In this task, logic played an essential part. I encoded the legal constraints  into a logical language, and  developed a program, based on the Answer Set Programming paradigm, to find optimal random solutions for the problem at hand.
The program was accepted by the State parties, and is finally to be used on November 23rd, in a plenary meeting with the delegates of all the States for the official assignment of reviewers.

## Effects of misinformation diffusion during a pandemic

The role of misinformation diffusion during a pandemic is crucial. An aspect that requires particular attention in the analysis of misinfodemics is the rationale of the source of false information, in particular how the behavior of agents spreading misinformation through traditional communication outlets and social networks can influence the diffusion of the disease. We studied the process of false information transmission by malicious agents, in the context of a disease pandemic based on data for the COVID-19 emergency in Italy. We model communication of misinformation based on a negative trust relation, supported by findings in the literature that relate the endorsement of conspiracy theories with low trust level towards institutions. We provide an agent-based simulation and consider the effects of a misinfodemic on policies related to lockdown strategies, isolation, protection and distancing measures, and overall negative impact on society during a pandemic. Our analysis shows that there is a clear impact by misinfodemics in aggravating the results of a current pandemic.

KEYWORDS  Misinformation, Misinfodemics, Multi-Agent Systems

Prandi, L., Primiero, G. Effects of misinformation diffusion during a pandemic. Appl Netw Sci 5, 82 (2020). https://doi.org/10.1007/s41109-020-00327-6 (Open Access)