Английская Википедия:Birkhoff's axioms

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Шаблон:Short description In 1932, G. D. Birkhoff created a set of four postulates of Euclidean geometry in the plane, sometimes referred to as Birkhoff's axioms.[1] These postulates are all based on basic geometry that can be confirmed experimentally with a scale and protractor. Since the postulates build upon the real numbers, the approach is similar to a model-based introduction to Euclidean geometry.

Birkhoff's axiomatic system was utilized in the secondary-school textbook by Birkhoff and Beatley.[2] These axioms were also modified by the School Mathematics Study Group to provide a new standard for teaching high school geometry, known as SMSG axioms. A few other textbooks in the foundations of geometry use variants of Birkhoff's axioms.[3]

Postulates

The distance between two points Шаблон:Math and Шаблон:Math is denoted by Шаблон:Math, and the angle formed by three points Шаблон:Math is denoted by Шаблон:Math.

Postulate I: Postulate of line measure. The set of points Шаблон:Math on any line can be put into a 1:1 correspondence with the real numbers Шаблон:Math so that Шаблон:Math for all points Шаблон:Math and Шаблон:Math.

Postulate II: Point-line postulate. There is one and only one line Шаблон:Math that contains any two given distinct points Шаблон:Math and Шаблон:Math.

Postulate III: Postulate of angle measure. The set of rays Шаблон:Math through any point Шаблон:Math can be put into 1:1 correspondence with the real numbers Шаблон:Math so that if Шаблон:Math and Шаблон:Math are points (not equal to Шаблон:Math) of Шаблон:Math and Шаблон:Math, respectively, the difference Шаблон:Math of the numbers associated with the lines Шаблон:Math and Шаблон:Math is Шаблон:Math. Furthermore, if the point Шаблон:Math on Шаблон:Math varies continuously in a line Шаблон:Math not containing the vertex Шаблон:Math, the number Шаблон:Math varies continuously also.

Postulate IV: Postulate of similarity. Given two triangles Шаблон:Math and Шаблон:Math and some constant Шаблон:Math such that Шаблон:Math and Шаблон:Math, then Шаблон:Math, and Шаблон:Math.

See also

References