Problèmes de méthode d'une analyse historique (I). Le Valenciennois industriel (1913-1950). Cohérence et incohérence d'un espace géonomique

[eng] Methodological problems of an historical analysis industry in the region of Valenciennes (1913-1950) : consistency and inconsistency of an geonomic space.. . In this article, the author presents the method she thinks she can use for the study of an important economie region in France -. the region of Valenciennes from 1913 to 1950. The author draws her inspiration from the mathematical models proposed by contemporary economists. She studies : the concept of economic space which leads to the matrix algebra applied to the life of a region; the concept of polarized space, of leading or derived area ; the concept of flow. The author insists on the products flows and the money flows which characterize this region, and she splits the latter into wage flows and capital flows (earned dividends, invested capital). She tries to discover the reason why after the 1930's, capitalists have inverted regional flows (more money transferred than invested).. This study cannot aspire to a great mathematical accuracy, the concepts of real and fiscal depreciation being fundamentally different. However, one can make an attempt at some approximations which will permit to carry ouf some of the input-output calculations often proposee. The author is very doubtful about the validity of the matrix algebra applied to Economics (is the regional space a vector space?). She brings more interest to the theory of graphs of fluence (also called theory of graphs of transfer). [fre] Problèmes de méthode d'une analyse historique. Le valenciennois industriel (1913-1950) : cohérence et incohérence d'un espace géonomique. . Cet article présente la .méthode que l'auteur pense pouvoir appliquer à l'étude d'une importante région économique française : le Valenciennois des années 1913 à 1950. L'auteur s'inspire des modèles mathématiques proposés par les économistes modernes: notion d'espace économique d'où dérive le calcul matriciel appliqué à la vie d'une région ; notion d'espace polarisé, de pôle de croissance, de pôles dérivés ; notion de flux ; l'auteur insiste sur les flux de produits et les flux d'argent qui caractérisent cette région et subdivise les flux d'argent en flux salariaux et flux capitalistes (dividendes extraits, capitaux investis). Il essaie de découvrir pour quelles raisons les capitalistes, à partir des années 30, ont inversé le solde des flux régionaux (argent transféré supérieur à argent investi). L'étude effectuée ne peut prétendre à une grande rigueur mathématique, les notions d'amortissement réel et fiscal étant fondamentalement différentes. Cependant des approximations peuvent être tentées, qui permettront de mener à bien quelques-uns des calculs matriciels souvent proposés. L'auteur exprime d'autre part de grandes réserves sur la validité du calcul matriciel appliqué à l'économie (l'espace régional est-il un espace vectoriel?). Plus intéressante lui apparaît la théorie de graphes de .fluence, aussi appelée théorie des graphes de. transfert. purpose, in spite of some drawbacks (its location, the lack of near by markets, the inadequacy of the means of conveyance...).. Its launching by Decazes in the 1820's constituted a genuine innovation and Decazeville became rapidly one of the leading metallurgic centers in France. But the exhaustion of the iron mines, financial difficulties, the lack of diversification in the production made it difficult for Decazeville to get successfully over the technical revolution in the steel production. During the last third of the XIXth century, Decazeville was gradually overshadowed by other rising enterprises and areas. The situation improved at the beginning of the XXth century, and especialey during World War I, but the interwar period witnessed a further decline, due to a lack of modernization. After World War II, the metallurgic and mining activities disappeared almost completely in front of the competition of new sources of energy and enterprises where production costs were appreciably lower. As tue can see, Decazeville is a good example of the birth, life, and death of a leading area.