Decision Forest: A Nonparametric Approach to Modeling Irrational Choice

Customer behavior is often assumed to follow weak rationality, which implies that adding a product to an assortment will not increase the choice probability of another product in that assortment. However, an increasing amount of research has revealed that customers are not necessarily rational when making decisions. In this paper, we propose a new nonparametric choice model that relaxes this assumption and can model a wider range of customer behavior, such as decoy effects between products. In this model, each customer type is associated with a binary decision tree, which represents a decision process for making a purchase based on checking for the existence of specific products in the assortment. Together with a probability distribution over customer types, we show that the resulting model -- a decision forest -- is able to represent any customer choice model, including models that are inconsistent with weak rationality. We theoretically characterize the depth of the forest needed to fit a data set of historical assortments and prove that with high probability, a forest whose depth scales logarithmically in the number of assortments is sufficient to fit most data sets. We also propose two practical algorithms -- one based on column generation and one based on random sampling -- for estimating such models from data. Using synthetic data and real transaction data exhibiting non-rational behavior, we show that the model outperforms both rational and non-rational benchmark models in out-of-sample predictive ability.Comment: The paper is forthcoming in Management Science (accepted on July 25, 2021

Standard genetic code: p-adic modelling, nucleon balances and selfsimilarity

This paper represents the preliminary results and conclusions on the one of fundamental questions of the genetic code related to the underlying selective mechanisms involved in its origin and evolution, in particular their hypothetical different nature, originally considered in [1,2,3]. A novel approach is introduced, based on known arithmetic regularities inside the genetic code, determined by the nucleon balances of amino acids and their divisibility by the decimal number 37 [4]. As a parameter of the genetic code systematization is introduced an aggregate nucleon number of amino acid and cognate codon, while divisibility test is carried out not only by the number 37, but also by 13.7, the selfsimilarity constant of decimal scaling [5]. Relevant nucleon sums were obtained for the most prominent divisions of the standard genetic code (SGC) according to p-adic model of the vertebrate mitochondrial code (VMC) in [6]. The nucleon number divisibility pattern of 37 and 13.7 for the RNA and DNA codon space, as well as for the amino acid space is also analyzed. The obtained results, particularly a general higher divisibility of the nucleon sums by the numbers 37 and 13.7 in SGC than in VMC, as well as a correspondence between the nucleon number divisibility pattern of both the RNA codon space and the amino acid space of SGC, how separately so conjointly, with the code degeneracy pattern, suggest some conclusions: support the hypothesis [1,2,3,7] that the selective driving forces acting during an emergence (an ancient phase) and an evolution (a modern phase) of the genetic code are different, imply the existence of an environmental-dependent stereochemical mechanism throughout the entire period of the genetic code emergence and support a mineral-mediated origin of the genetic code [7,8]

Alois Halder, Filozofijski rječnik

Prikaz knjige Alois Halder, Filozofijski rječnik, uredio Jure Zovko, prijevod s njemačkog Ante Sesar, Naklada Jurčiæ, Zagreb 2002, 463 str

Serbo-Albanian bank in Albania 1925-1927

The Serbo-Albanian Bank was founded at Cetinje in 1922, at the time Yugoslav-Albanian diplomatic relations were established, with the purpose of opening its branch offices in Albania in order to contribute to closer economic relations between the two neighboring countries. The Bank was unable to achieve its goal in the first two years of operation, as it had not obtained the necessary licenses from the Albanian authorities. The branch office in Scutari was opened only in early 1925. Another topical issue at the time was the creation of the Albanian National Bank as the central monetary institution that would function as a regulator of the entire economic life of Albania. Supported by the Yugoslav state, the Serbo-Albanian Bank planned its transformation into an Albanian central bank, but without success. Namely, it was Italian capital that assumed a leading role in the Albanian National Bank founded in September 1925. In spite of this failure, the branch office of the Serbo-Albanian Bank commenced its operations in Albania. Under its roof, it set up the Privileged Trading Agency, and expressed interest in obtaining exploration and excavation concessions for the copper mine in the region of Puka in northern Albania. It was granted the concession by the Albanian government, but failed to set up a copper exploitation company. Facing numerous difficulties, the major of which was lack of the necessary cash for operation and significant business losses in Albania, the branch office was closed in 1927, pursuant to the decision of the Cetinje headquarters