Multiclass classificationIn machine learning and statistical classification, multiclass classification or multinomial classification is the problem of classifying instances into one of three or more classes (classifying instances into one of two classes is called binary classification). While many classification algorithms (notably multinomial logistic regression) naturally permit the use of more than two classes, some are by nature binary algorithms; these can, however, be turned into multinomial classifiers by a variety of strategies.
Orange (colour)Orange is the colour between yellow and red on the spectrum of visible light. Human eyes perceive orange when observing light with a dominant wavelength between roughly 585 and 620 nanometres. In traditional colour theory, it is a secondary colour of pigments, produced by mixing yellow and red. In the RGB colour model, it is a tertiary colour. It is named after the fruit of the same name. The orange colour of many fruits and vegetables, such as carrots, pumpkins, sweet potatoes, and oranges, comes from carotenes, a type of photosynthetic pigment.
Positioning (marketing)Positioning refers to the place that a brand occupies in the minds of the customers and how it is distinguished from the products of the competitors and different from the concept of brand awareness. In order to position products or brands, companies may emphasize the distinguishing features of their brand (what it is, what it does and how, etc.) or they may try to create a suitable (inexpensive or premium, utilitarian or luxurious, entry-level or high-end, etc.) through the marketing mix.
Gentzen's consistency proofGentzen's consistency proof is a result of proof theory in mathematical logic, published by Gerhard Gentzen in 1936. It shows that the Peano axioms of first-order arithmetic do not contain a contradiction (i.e. are "consistent"), as long as a certain other system used in the proof does not contain any contradictions either. This other system, today called "primitive recursive arithmetic with the additional principle of quantifier-free transfinite induction up to the ordinal ε0", is neither weaker nor stronger than the system of Peano axioms.
EquiconsistencyIn mathematical logic, two theories are equiconsistent if the consistency of one theory implies the consistency of the other theory, and vice versa. In this case, they are, roughly speaking, "as consistent as each other". In general, it is not possible to prove the absolute consistency of a theory T. Instead we usually take a theory S, believed to be consistent, and try to prove the weaker statement that if S is consistent then T must also be consistent—if we can do this we say that T is consistent relative to S.
