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A hyperplane arrangement is called formal provided all linear dependencies among the defining forms of the hyperplanes are generated by ones corresponding to intersections of codimension two. The significance of this notion stems from the fact that complex arrangements with aspherical complements are formal. The aim of this note is twofold. While work of Yuzvinsky shows that formality is not combinatorial, in our first main theorem we prove that the combinatorial property of factoredness of arrangements does entail formality. Our second main theorem shows that formality is hereditary, i.e., is passed to restrictions. This is rather counter-intuitive, as in contrast the known sufficient conditions for formality, i.e., asphericity, freeness and factoredness (owed to our first theorem), are not hereditary themselves. We also demonstrate that the stronger property of k-formality, due to Brandt and Terao, is not hereditary.

We explore various formality and finiteness properties in the differential graded algebra models for the Sullivan algebra of piecewise polynomial rational forms on a space. The 1 -formality property of the space may be reinterpreted in terms of the filtered and graded formality properties of the Malcev Lie algebra of its fundamental group, while some of the finiteness properties of the space are mirrored in the finiteness properties of algebraic models associated with it. In turn, the formality and finiteness properties of algebraic models have strong implications on the geometry of the cohomology jump loci of the space. We illustrate the theory with examples drawn from complex algebraic geometry, actions of compact Lie groups, and 3 -dimensional manifolds.

Olympic event zones are characterized as being intensely formally regulated during live staging periods, producing exclusionary environments blamed for sidelining host community interests. Yet, our findings contradict what scholars perceive to be inflexible formal regulations, and, the regulator's ability to take informal action. By interviewing and drawing on the experience of 17 regulators during London 2012 we identify how regulators simultaneously oscillate between modes of regulatory formality and informality, straddling what is referred to as the \"formality-informality span.\" Our application and theorization of these concepts critiques existing explanations of how regulation is enacted in mega-sporting events, providing new insights into the way organizers balance regulatory demands and potentially opening up new emancipatory policies and more equitable outcomes for host communities.

Olympic event zones are characterised as being intensely formally regulated during live staging periods, producing exclusionary environments blamed for side-lining host community interests. Yet, our findings contradict what scholars perceive to be inflexible formal regulations, and, the regulator’s ability to take informal action. By interviewing and drawing on the experience of 17 regulators during London 2012 we identify how regulators simultaneously oscillate between modes of regulatory formality and informality, straddling what is referred to as the ‘formality-informality span’. Our application and theorisation of these concepts critiques existing explanations of how regulation is enacted in mega-sporting events, providing new insights into the way organisers balance regulatory demands and potentially opening up new emancipatory policies and more equitable outcomes for host communities.

Researchers primarily focus on the formal practices used by event organisers to establish temporary spaces like Host Event Zones, characterised as a unilateral process that ignores community interests. Yet little research investigates both the formal and informal interactions between stakeholders. Interviews with London 2012 senior organisers after the ‘fog of organising’ has lifted – and without political pressure to toe-the-line – reveals how two-way dialogue was facilitated through various communicative mechanisms, from ‘road shows’ to more inclusive Olympic Organising Committee meetings. This counters previous arguments and contributes new knowledge by revealing – and more accurately representing - how event zones are co-created through negotiation between the event and community. Consequently, scholars should be wary of extrapolating from formal practices on paper and interrogate the more complex and messy informalities of planning to improve veracity of claim(s).

In recent years, scholars in migration, urban studies, and urban planning have increasingly focused on the diversity of arrival processes experienced by international newcomers and the variety of spatial settings they involve. Current research on arrival infrastructures focuses on both place-based opportunity structures and newcomers’ agency in shaping arrival processes, illustrating the interconnectedness of formal and informal infrastructures. Arrival infrastructuring can be understood as a mediating process that connects individuals and their social, economic, and cultural capital to places and societal resources. The concept of “in/formality,” which addresses the formal–informal nexus as a continuum rather than in binary terms, offers a valuable yet underexplored perspective to analyse arrival processes and actors involved, including the state, market, and old and new residents. Through the lens of in/formality, this thematic issue aims to explore the practices, negotiations, and interconnections among different (migrant and non-migrant) actors involved in arrival infrastructuring. The contributions highlight four recurring ways in which the interplay between informal and formal practices manifests: unusual alliances, brokering, boundary spanning, and structured workarounds.

Let$p$be a prime number and let$F$be a field of characteristic different from$p$. We prove that there exist a field extension$L/F$and$a,b,c,d$in$L^{\\times }$such that$(a,b)=(b,c)=(c,d)=0$in$\\mathrm {Br}(L)[p]$but the mod p Massey product$\\langle a,b,c,d\\rangle$is not defined over$L$. Thus, the strong Massey vanishing conjecture at the prime$p$fails for$L$, and the cochain differential graded ring$C^{* }(\\Gamma _L,\\mathbb Z/p\\mathbb Z)$of the absolute Galois group$\\Gamma _L$of$L$is not formal. This answers a question of Positselski. As our main tool, we define a secondary obstruction that detects non-triviality of unramified torsors under tori, and which is of independent interest.

This study offers a systematic comparison of automated content analysis tools. The ability of different lexicons to correctly identify affective tone (e.g., positive vs. negative) is assessed in different social media environments. Our comparisons examine the reliability and validity of publicly available, off-the-shelf classifiers. We use datasets from a range of online sources that vary in the diversity and formality of the language used, and we apply different classifiers to extract information about the affective tone in these datasets. We first measure agreement (reliability test) and then compare their classifications with the benchmark of human coding (validity test). Our analyses show that validity and reliability vary with the formality and diversity of the text; we also show that ready-to-use methods leave much space for improvement when analyzing domain-specific content and that a machine-learning approach offers more accurate predictions across communication domains.

Researchers primarily focus on the formal practices used by event organizers to establish temporary spaces like Host Event Zones, characterized as a unilateral process that ignores community interests. Yet little research investigates both the formal and informal interactions between stakeholders. Interviews with London 2012 senior organizers after the \"fog of organizing\" has lifted-and without political pressure to toe-the-line-reveals how two-way dialogue was facilitated through various communicative mechanisms, from \"road shows\" to more inclusive Olympic Organizing Committee meetings. This counters previous arguments and contributes new knowledge by revealing-and more accurately representing-how event zones are cocreated through negotiation between the event and community. Consequently, scholars should be wary of extrapolating from formal practices on paper and interrogate the more complex and messy informalities of planning to improve veracity of claim(s).

Recent research on informality in Colombia shows that reforms aimed at stimulating the demand for formal employment by reducing corporate taxes have had only modest effects on the relative size of informal employment. Given the apparent limits of demand-side policies and considering that 73 % of informal workers are self-employed this paper examines the incentives that influence the supply of formal labour. Specifically, it quantifies the monetary costs faced by informal work­ers when deciding to become formal. The paper defines the potential monetary loss associated with formali­sation through the Formalisation Tax Rate (FTR) and calculates it across several simulated scenarios. When the monetary benefits granted by law to formal employ­ees are included (such as family and transport subsidies and mandatory bonuses), some informal employees may have an incentive to formalise. However, self-employed workers—who make up the majority of informal employ­ment—would have no incentive to enter formal work unless their income base were raised to at least the level of the monthly minimum wage. Las investigaciones recientes sobre la informalidad en Colombia indican que las reformas que buscaban incrementar la demanda de empleo formal por medio de reducciones en los impuestos a las empresas tuvie­ron efectos modestos en el tamaño relativo del empleo informal. En atención a este agotamiento de las políticas orientadas a la demanda y el hecho de que el 73 % de los trabajadores informales son independientes, se analizan los incentivos a la oferta de empleo formal. Más especí­ficamente, se cuantifican los incentivos monetarios que tienen los trabajadores informales para ingresar en el empleo formal. Se define la potencial pérdida monetaria de la formalización en relación con los ingresos informa­les por medio de la tasa impositiva a la formalización (TIF). Se calcula la TIF en varios escenarios simulados. Si se con­sideran los beneficios que la ley otorga a los empleados formales (por ejemplo, subsidios familiares, de transporte, entre otros), algunos asalariados informales tendrían un incentivo a ser formales, pero los trabajadores indepen­dientes que constituyen la mayor parte del empleo informal no tendrían incentivos a menos que su salario base sea incrementado, al menos, hasta el salario mínimo mensual.