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  2. Many-to-many (data model) - Wikipedia

    en.wikipedia.org/wiki/Many-to-many_(data_model)

    For example, think of A as Authors, and B as Books. An Author can write several Books, and a Book can be written by several Authors. In a relational database management system, such relationships are usually implemented by means of an associative table (also known as join table, junction table or cross-reference table), say, AB with two one-to-many relationships A → AB and B → AB.

  3. Cardinality (data modeling) - Wikipedia

    en.wikipedia.org/wiki/Cardinality_(data_modeling)

    The entity–relationship model proposes a technique that produces entity–relationship diagrams (ERDs), which can be employed to capture information about data model entity types, relationships and cardinality. A Crow's foot shows a one-to-many relationship. Alternatively a single line represents a one-to-one relationship. [4]

  4. Polynomial regression - Wikipedia

    en.wikipedia.org/wiki/Polynomial_regression

    The least-squares method was published in 1805 by Legendre and in 1809 by Gauss. The first design of an experiment for polynomial regression appeared in an 1815 paper of Gergonne . [ 3 ] [ 4 ] In the twentieth century, polynomial regression played an important role in the development of regression analysis , with a greater emphasis on issues of ...

  5. Rank (linear algebra) - Wikipedia

    en.wikipedia.org/wiki/Rank_(linear_algebra)

    f is injective (or "one-to-one") if and only if A has rank n (in this case, we say that A has full column rank). f is surjective (or "onto") if and only if A has rank m (in this case, we say that A has full row rank). If A is a square matrix (i.e., m = n), then A is invertible if and only if A has rank n (that is, A has full rank).

  6. Object–relational mapping - Wikipedia

    en.wikipedia.org/wiki/Object–relational_mapping

    As well, objects are managed on-heap and are under full control of a single process, while database tuples are shared and must incorporate locking, merging, and retry. Object–relational mapping provides automated support for mapping tuples to objects and back, while accounting for all of these differences. [1]

  7. Correspondence analysis - Wikipedia

    en.wikipedia.org/wiki/Correspondence_analysis

    Correspondence analysis is performed on the data table, conceived as matrix C of size m × n where m is the number of rows and n is the number of columns. In the following mathematical description of the method capital letters in italics refer to a matrix while letters in italics refer to vectors .

  8. Maximum a posteriori estimation - Wikipedia

    en.wikipedia.org/wiki/Maximum_a_posteriori...

    The MAP can be used to obtain a point estimate of an unobserved quantity on the basis of empirical data. It is closely related to the method of maximum likelihood (ML) estimation, but employs an augmented optimization objective which incorporates a prior density over the quantity one wants to estimate.

  9. Logistic map - Wikipedia

    en.wikipedia.org/wiki/Logistic_map

    Both the logistic map and the sine map are one-dimensional maps that map the interval [0, 1] to [0, 1] and satisfy the following property, called unimodal . = =. The map is differentiable and there exists a unique critical point c in [0, 1] such that ′ =. In general, if a one-dimensional map with one parameter and one variable is unimodal and ...