Noël Bonneuil

Labour Market Participation of French Women over the Life Cycle, 1935–1990

Employment histories with multiple spells and time varyingcovariates help identify determinants of labour markettransitions of women in France between 1935 and 1990. Higher educatedwomen were more likely to become inactive, but returned to work also moreeasily, especially when they added work experience. Being married,whether mother or not, induced a rearrangement of time betweenstaying at home and labour, in rendering exit from employment morelikely and return from inactivity to employment less likely. Exits from employment were lessfrequent for mothers of larger families, while return toemployment decreased with the total number of children, in spite of thegrowing financial needs of larger families. Transitions betweenemployment and inactivity increased with favourable economicconditions. However, involuntary exits from employment were moreprobable during economic downturns.

Capital accumulation, inertia of consumption and norms of reproduction

A model of capital accumulation is built in relation with fertility and consumption. Avoiding to impose a direct analytical relationship between these three variables, the author studies the set of possible evolutions under the constraints imposed by the inertia of habit change.The conflict between the necessity to avoid impoverishment, the desire to increase consumption when possible and the reproduction intensity delineate the set of viable solutions and the set of attitudes leading to capital extinction. This qualitative view of change of behaviors provides an alternative explanation to historical fertility fluctuations outside the usual Easterlin framework.

Population viability in three trophic-level food chains

The perpetuation of three-trophic level ecosystems where the three species exhibit unpredictable time-varying survival strategies is described by a specific set, the viability kernel, gathering all states from which there exists at least one trajectory safeguarding each species over a given density threshold. The strategies permitting this property are delineated and called viable strategies. All solutions starting outside the viability kernel lead to too low densities or extinction. The viability approach highlights the timing of strategy changes necessary for a system to perpetuate itself or alternatively to lead one species to extinction. The study of the dependence of the viability kernel on the admissible sets of strategies reveals the minimal flexibilities necessary for the existence of the system. The shape of the viability kernel determines whether the exogenous addition or substraction of prey or predator will endanger the system or not, thus gathering different experiments with opposite results. The comparison of the coexistence kernel with viability kernels for one, two or three species points out the importance of repeated strategies, not necessarily in a periodic manner, thus emphasizing the concept of repetitions in ecosystems instead of cycles as a key feature of coexistence.

Malthus, boserup and population viability

The Malthus-Boserup explanatory framework is revisited from the point of view of viability theory. Instead of imposing a univocal relationship between population pressure and level of knowledge, the way technology will change is not determined, it is only constrained. This leads to regard any situation as associated to a set of reachable futures. When no possibility is left for systems to avoid extinction, systems are no longer viable. Hence, the control-phase space can be divided into regions corresponding to gradual danger or security. This point of view allows the introduction of ideas such as incentives to create or to use new knowledge, gives a role to the threatening power of Malthusian checks, and leaves space for a specific variety of behaviors. The Boserupian theme then appears indirectly, emerging from the constraints imposed by the inertia of technological change.

Optimal Population Path Fitting for Flawed Vital Statistics and Censuses

A problem, often encountered in the analysis of historical data, is the difficulty in overcoming missing or flawed data. Lotka-McKendrick discrete demographic model, including migration, is combined with stochastic optimization to fit available censuses and vital statistics series to reconstruct missing population data, in the presence of one or two censuses. Simulations help to calibrate the method and determine error weights associated with each data series. An empirical case study is made using data from an administrative subdivision in southern Russia for the period 1863–1916.

Familial components of first migrations after marriage in nineteenth-century France

To what extent did kin, notably parents and siblings, influence the risk of migration in nineteenth-century France? Personal networks and migratory chains have become a key explanation of mobility since Hägerstrand’s pioneering work. Hägerstrand used microhistorical data to highlight the role of networks in migration in and from Sweden. He showed their importance in explaining one of the deepest mysteries in migration studies: why do emigrants from villages go directly to certain destinations rather than to closer alternatives with similar economic opportunities? Hägerstrand’s ideas helped us to understand why some poor countries have few out-migrants to wealthy countries while others experience massive moves, why industrialized countries attract migrants from specific countries and not others, or why all migrants coming from a specific valley, after travelling across oceans or continents, settle into the same city. A striking contemporary example is the settlement of Chinese migrants from two cities (Wenzhou and Quingtian) in France in the 1990s: they reunited with a group of kin descended from Chinese workers recruited for arms factories and excavation work during the First World War. Explaining migration through analysing kin networks poses two problems, which we address here:

Viability in dynamic social networks

Two examples, Sampsons monks and Padgett and Ansell’ Florentines, illustrate the viability approach of dynamic networks. Notably, the relationship with centrality is studied. Historical processes involving networks are discussed. Networks are presented as controls in controlled dynamic systems. Viability is the property for a state x that there exists a trajectory starting from x and satisfying the constraints until the time horizon. To obtain this, connection matrices must be selected at each time and each visited state among a specific set, the regulation map, which is carefully defined and built.

Maximum under continuous-discrete-time dynamic with target and viability constraints

The viable maximum of of a continuous function L ∈ ℒ1(ℝ2m+1, ℝ+) under a dynamic x′(t) ∈ F(x(t)) under constraint x(t) ∈ K where K is closed is obtained on the boundary of the capture-viability kernel in the direction of high y of the target K × {0} viable in K × ℝ+ under the extended dynamic (x′(t), y′(t)) ∈ (F(x(t)), −L(x(t), u(t))). The result holds true with discrete-continuous-time measurable controls. Example and application to hybrid dynamics under viability constraints and target are given.

Viable Ramsey economies

The Ramsey model of economic growth is revisited from the perspective of viability theory. The Ramsey model, augmented with minimal consumption and sustainability criteria, becomes a viability problem. The framework allows for a clear picture of optimal viable, optimal nonviable, and viable nonoptimal paths. The drastic sacrifices in terms of present consumption required by the implementation of Brundtland sustainability are visualized, the rich countries bearing the major part of the burden. The econometric analysis of viability sets enhances the role of technological progress in ensuring Brundtland sustainability. Preference parameters such as the pure time preference rate are statistically nonsignificant.

Optimal Marriage Fitting for Imperfect Statistics

The reconstruction of the marriage market from imperfect records is solved by the minimization of a distance to the observations under civil status-specific McKendrick dynamics. To do this, the completion each year of the distribution of ages of bride and groom is also obtained by minimization under the constraints of recorded table margins, avoiding the recourse to ad hoc stylized functions. An empirical case study is presented using data from an administrative subdivision in southern Russia for the period 1867–1916.