# Talk:Squeeze mapping

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## Diagram produced

The squeeze mapping has been illustrated in the Modenov & Parkhomenko book listed in the references. This diagram was also printed in Varieties of Realism, appendix A, page 290, by M. A. Hagen (1986). The caption there is "perpendicular axes of compression" which isn't helpful. The squeeze mapping can convert ellipse to circle to ellipse, and the oval-circle-oval idea of the above print illustrations would improve Wikipedia.Rgdboer (talk) 01:23, 7 November 2009 (UTC)

Apologies for the very long delay - would this be fine?
A hyperbolic sector and rectangles in a squeeze mapping. The area of the sector and rectangle is preserved in the mapping.
The rectangles are included since it's easier to see the construction of the hyperbolic sector, and it's clearer that the area is preserved. Maschen (talk) 19:24, 1 December 2012 (UTC)

Thank you Maschen for an excellent illustration worthy of meditation. It has been placed in the Literature section. The principles shown by your work makes the efforts of the cited authors meld into the essential nature of the squeeze mapping.Rgdboer (talk) 00:04, 2 December 2012 (UTC)

## Mentions

Mellin Haskell wrote an article that relates the squeeze mapping to hyperbolic sector areas and hyperbolic angle as used with hyperbolic functions. Before that article was found, several sources where cited where the squeeze mapping was applied. Superfluous now with Haskell's complete treatment, the mentions previously used in the article are listed here:

• William Kingdon Clifford was the author of Common Sense and the Exact Sciences, published in 1885. In the third chapter on Quantity he discusses area in three sections. Clifford uses the term "stretch" for magnification and the term "squeeze" for contraction. Taking a given square area as fundamental, Clifford relates other areas by stretch and squeeze. He develops this calculus to the point of illustrating the addition of fractions in these terms in the second section. The third section is concerned with shear mapping as area-preserving.
• The myth of Procrustes is linked with this mapping in a 1967 educational (SMSG) publication:
Among the linear transformations, we have considered similarities, which preserve ratios of distances, but have not touched upon the more bizarre varieties, such as the Procrustean stretch (which changes a circle into an ellipse of the same area).
Coxeter & Greitzer, pp. 100, 101.
• Attention had been drawn to this plane mapping by Modenov and Parkhomenko in their Russian book of 1961 which was translated in 1967 by Michael B. P. Slater. It included a diagram showing the squeezing of a circle into an ellipse.
• P. S. Modenov and A. S. Parkhomenko (1965) Geometric Transformations, volume one. See pages 104 to 106.
• Werner Greub of the University of Toronto includes "pseudo-Euclidean rotation" in the chapter on symmetric bilinear functions of his text on linear algebra. This treatment in 1967 includes in short order both the diagonal form and the form with sinh and cosh.
• The Mathematisch Centrum Amsterdam published E.R. Paërl's Representations of the Lorentz group and Projective Geometry in 1969. The squeeze mapping, written as a 2 × 2 diagonal matrix, Paërl calls a "hyperbolic screw".
• In his 1999 monograph Classical Invariant Theory, Peter Olver discusses GL(2,R) and calls the group of squeeze mappings by the name the isobaric subgroup. However, in his 1986 book Applications of Lie Groups to Differential Equations (p. 127) he uses the term "hyperbolic rotation" for an equivalent mapping.
• In 2004 the American Mathematical Society published Transformation Groups for Beginners by S.V. Duzhin and B.D. Chebotarevsky which mentions hyperbolic rotation on page 225. There the parameter r is given as et and the transformation group of squeeze mappings is used to illustrate the invariance of a differential equation under the group operation.

A new section "Logarithm and hyperbolic angle" has been written to make a digest of Haskell's appreciation of the squeeze.Rgdboer (talk) 01:30, 29 December 2014 (UTC)