To expand search, see Geometric Theorems.
The Mathematics and the Liberal Arts pages are intended to be a resource for student research projects and for teachers interested in using the history of mathematics in their courses. Many pages focus on ethnomathematics and in the connections between mathematics and other disciplines. The notes in these pages are intended as much to evoke ideas as to indicate what the books and articles are about. They are not intended as reviews. However, some items have been reviewed in Mathematical Reviews, published by The American Mathematical Society. When the mathematical review (MR) number and reviewer are known to the author of these pages, they are given as part of the bibliographic citation. Subscribing institutions can access the more recent MR reviews online through MathSciNet.
Anagnostakis, Christopher and Goldstein, Bernard R. On an error in the Babylonian table of Pythagorean triples. Centaurus 18 (1973/74), 64--66. (Reviewer: E. M. Bruins.) SC: 01A15, MR: 58 #20994.
The authors explain a well-known mistake in the Babylonian tablet Plimpton 322 (column I, entry 10) as a consequence of a certain method of computation and of the neglect of a medial zero. It is a very appealing theory, and could give us some insight the way Babylonians did their mathematics. Other solutions have also been proposed. A good example of how we can learn from mistakes! Closely related topics: Sumerians and Babylonians and Algorithms.
Chorbachi, W. K. In the tower of Babel: beyond symmetry in Islamic design. Symmetry 2: unifying human understanding, Part 2. Comput. Math. Appl. 17 (1989), no. 4-6, 751--789. (Reviewer: Marjorie Senechal.) SC: 01A99 (01A30 92K99), MR: 91a:01058c.
An interesting and personal account of how the author discovered geometric manuscripts written for Islamic artisans. With this discover, the author gives a new historical and scientific basis to the study of certain kinds of Islamic art. Much work preceding the author's had focused on religious, mystical, or perceptual interpretations of the work. Many ideas were primarily hypothetical, such as the (incorrect) idea that all Islamic art derives from the circle. The author suggests that many religious and mystical interpretations of Islamic geometric art should not be regarded as being historically based. Instead, the author shows how some Islamic art is highly mathematical, showing concerns with such topics as Pythagorean triangles and the notion of similarity (he gives an example where a shape appears in three different scales, each similar shape being derived from the last by a clever process). Much of the article discusses these in the context of a cyclic quadrilateral appearing in Islamic art with sides 1, 2, 2, 71/2. The author even noted an Islamic anticipation of a shape used to produce Penrose tilings. The author suggests that symmetry groups, while useful, can not alone give a full understanding of Islamic art. Closely related topics: The Islamic World, Art, Plane Patterns, Penrose Tilings, Religion, and Mathematics and Mysticism.
Dibble, William E. A possible Pythagorean triangle at Stonehenge. J. Hist. Astronom. 7 (1976), no. 2, 141--142. (Reviewer: C. R. Fletcher.) SC: 01A10, MR: 58 #20990a.
Dibble notes that one triangle at Stonehenge is rather close to a 5,12,13 Pythagorean right triangle. The conclusion is bound to be controversial, and Dibble is cautious about making definite claims. Closely related topic: The Stone Builders.
Engels, Hermann. Quadrature of the circle in ancient Egypt. Historia Math. 4 (1977), 137--140. (Reviewer: L. Guggenbuhl.) SC: 01A15, MR: 56 #5124.
Explains the Egyptian formula for the area of a circle in terms of the practices of Egyptian stone masons. In order to form a relief, the stone masons covered their designs with a grid. The hypothesized construction involves an error which would confirm the now commonly held view that the ancient Egyptians did not properly understand the Pythagorean theorem. Closely related topics: Ancient Egypt, The Circle, and Coordinates.
Gerdes, Paulus P. J. On ethnomathematical research and symmetry. Symmetry in a kaleidoscope, 2. Symmetry Cult. Sci. 1 (1990), no. 2, 154--170. SC: 01A07, MR: 1 188 949.
Gerdes begins with a discussion of why symmetry is such a common phenomenon in human culture. He notes that some symmetries which are rare in nature (e.g., rotational symmetries of order 2) are common amongst us. Gerdes gives the example of rotational symmetry being used in the tattoos of the Makonde of northern Mozambique. Gerdes explains how symmetries such as the rotational symmetry of order 2 can arise naturally in solving problems in such areas as weaving. Gerdes then turns to the geometry of the line drawings made by the Tamil women in South India (during harvest month) and those made by the Tshokwe. These drawings have some strong similarities, and in both cases show an interest in tracing out a figure with a single continuous line. They also show a strong interest in symmetry, and Gerdes gives examples of how designs which fail to follow the one-line cultural norm may also fail to display the expected symmetries, suggesting that such drawings are degradations of more symmetric ones drawn with one line. The author advances a construction principle that can be used to construct both the Tamil and Tshokwe patterns. (Although the author doesn't note this, it is interesting that this principle is very similar to another principle that has been advanced for Celtic knot friezes!) Gerdes then discusses some mathematical properties of curves made using his construction principle. He also discusses some other interesting topics in his ethnomathematical research. For example, the author mentions that he has a found a new hypothesis on the origin of the Egyptian formula for the volume of a truncated pyramid, and has also found an infinite series proof for the Pythagorean theorem. Closely related topics: Symmetry, The Tamil of South India, TheTshokwe, Continuous Tracing Problems, The Celts, and Ancient Egypt. Also possibly relevant: Mozambique, Tattoos, and Weaving.
Knorr, W. R. The geometer and the archaeoastronomers: on the prehistoric origins of mathematics. Review of: Geometry and algebra in ancient civilizations [Springer, Berlin, 1983; MR: 85b:01001] by B. L. van der Waerden. British J. Hist. Sci. 18 (1985), no. 59, part 2, 197--212. SC: 01A10, MR: 87k:01003.
The reviewer discusses van der Waerden's book Geometry and Algebra in Ancient Civilizations. Although the reviewer clearly admires van der Waerden for his work in algebra and in the history of mathematics in general, he is highly critical of the conclusions reached in van der Waerden's book. A basic theme of the book is that there is a pre-Babylonian ancestor to mathematics in Babylonia, ancient Egypt, Greece, China and India; thus the book can therefore be thought of in part as a further development of Abraham Seidenberg's theories on the ritual origins of ancient mathematics. The reviewer takes issue with several facts cited in the book, and in addition with three assumptions that he sees van der Waerden using explicitly or implicitly in the book: "(1) independent discovery is so rare that it may effectively be discounted as a working hypothesis for relating technical traditions; (2) derivative traditions are inferior to their source traditions; (3) borrowing from one tradition to another is not selective, but entails the adoption of whole bodies of technique." (The phrase "inferior to" in (2) could just as well be replaced by "degraded in".) The reviewer suggests in addition that van der Waerden has not been sufficiently critical in accepting claims by Alexander Thom and others about advanced mathematics in megalithic monuments, and sees these claims as forming "the veritable linchpin of van der Waerden's thesis". The author briefly discusses some of Thom's work in megalithic mathematics, and concludes that he finds no real evidence of the Pythagorean theorem, the ellipse, or a standard unit of distance in neolithic times. The review concludes with the statement "I fear even more the regrettable impact on credulous nonspecialists who may not know to distinguish between the general enterprise of scientific research and the reckless notions of some scientists." Closely related topics: Sumerians and Babylonians, Ancient Egypt, Greece, China, India, The Stone Builders, and Alexander Thom.
Llyod, Daniel B. Further Evidences of Primeval Mathematics. Mathematics Teacher 57 (1966), 668--70.
A tablet from a dig at Tel Dhibayi near Baghdad shows how to find the dimensions of a triangle from its diagonal and area. The solution requires a knowledge of the Pythagorean theorem, and artfully sidesteps the difficulty of solving a quadratic equation by solving a pair of simple linear equations. Many other articles discuss similar tablets and solutions, but few so concisely as this. However, note that in the context of other Babylonian sources, the method of solution may be less obscure than the author seems to suggest. Reprinted in Swetz, Frank J., From Five Fingers to Infinity. Closely related topics: Sumerians and Babylonians and The Quadratic Formula.
Lumpkin, Beatrice. Note: the Egyptians and Pythagorean triples. Historia Math. 7 (1980), no. 2, 186--187. SC: 01A15, MR: 81c:01004.
The author notes that some ancient Egyptian problems suggest a knowledge of certain Pythagorean triangles. For example, in the Berlin Papyrus there are problems where a given square is to be written as the sum of two squares in a given ratio. The solutions involve the fact that 62+82=102 and 122+162=202; these facts are familiar to us from our knowledge of the (3,4,5) right triangle. She also notes that the Egyptian units of measurement suggest a knowledge of the Pythagorean theorem in the special case of an isosceles right triangle. "The double remen is the diagonal of a square whose side was one cubit. By changing the units of measurement from cubits to double remens, the area of a figure would be doubled." Closely related topic: Ancient Egypt.
Palter, Robert. Black Athena, Afro-centrism, and the history of science. Hist. Sci. 31 (1993), no. 93, part 3, 227--287. (Reviewer: Donald Cook.) SC: 01A16 (01A07 01A20 01A70), MR: 94i:01001.
Martin Bernal's Black Athena created a bit of a sensation when it first came out. Robert Palter discusses aspects of Bernal's article and also other arguments of afro-centrists. Palter particularly focuses on the question of whether Egyptian mathematics and science influenced the Greeks. Bernal suggests that the influence may be quite large, and Palter argues that all existing evidence points to the influence being quite small. An important area in Palter's discussions is ancient astronomy, where Palter discusses the general character of Egyptian astronomy, and argues that some claims about it have been vastly exaggerated; much of this discussion focuses on discrediting claims made by John Pappademos. Palter then notes that Peter Tompkins, author of Secrets of the Great Pyramid, seems to suggest that Newton was led by Egyptian science to discover his law of gravitation. About Tompkins, Bernal writes that "it it a tragedy that Tompkins's brilliant and scholarly book has been stripped of its scholarly apparatus". Palter writes "It seems never to have occurred to Bernal that the absence of scholarly apparatus in Tompkins's account of Newton has a very simple explanation: no scholarly evidence exists to support that account." When discussing Egyptian mathematics proper, Palter focuses discusses the general character, and then square roots (or a relative lack of them), the value of pi, the controversial problem in the Moscow papyrus on the surface area of a basket, the Pythagorean theorem (or the relative lack of it, arguments on the special case of involving the diagonal of the square), and the notion (or absence of notion) of an irrational number. Palter attacks claims by Cheikh Anta Diop (see Civilization or barbarism: An authentic anthropology) that Archimedes stole some of his most famous mathematics from the Egyptians. Palter then discusses pyramidology, and some of the claims cited by Bernal that "one can find such relations as pi, phi, the 'golden number' and Pythagoras' triangle from them." The final section, discusses the similarities and differences between Egyptian and Greek medicine. Although Mathematics is not so directly involved here, strong Egyptian influence in Greek medicine could argue for the plausibility of influence of other Egyptian science on Greek science as well. A very interesting paper. Apart from the fact that Palter's article serves as a kind of review of Bernal's book, it is worth reading for its discussions on the nature of Egyptian mathematics and science. Bernal responds to Palter's article in Bernal, Martin, Response to a paper by R. Palter: "Black Athena, Afro-centrism, and the history of science" [Hist. Sci. 31 (1993), no. 93, part 3, 227--287; MR: 94i:01001]. Closely related topics: Ancient Egypt, Greece, Astronomy, Archimedes, The Egyptian Pyramids, and Medicine.
Shloming, Robert. Th\^abit ibn Qurra and the Pythagorean Theorem. Mathematics Teacher 63 (1970), 519--28.
Discusses the life and work of Th\^abit ibn Qurra, focusing on his work on the Pythagorean Theorem. Th\^abit gave two proofs of this theorem (both independently rediscovered in the early 1900s), and also a generalization to triangles that are not necessarily right-angled (independently rediscovered about 1665 by John Wallis). The author also discusses the Ishaq-Th\^abit translation of Euclid's Elements, which was the basis for the translation by Gerard of Cremona. Reprinted in Swetz, Frank J., From Five Fingers to Infinity. Closely related topic: Th\^abit ibn Qurra.
Swetz, Frank. The "Piling Up of Squares" in Ancient China. Mathematics Teacher 70 (1977), 72--79.
Chapter IX of the Chiu Chang Suan Shu has a series of interesting problems on the Pythagorean Theorem, many requiring a little resourcefulness to solve, even today. Two methods are used in Chapter IX. This article discusses one of these, the Chi-Chü, or "piling up of squares". This is a dissection method; thus areas are disassembled and reassembled in a different way. The author gives several examples. The last two are among the most interesting. They find the largest square and circle that can be drawn in a right triangle; only the case where the square includes the right angle seems to be considered. The methods are ingenious, and would make appealing classroom demonstrations. The Chi-Chü method is also used in problems that at first seem to have little to do with areas. Problem 14 is an example:Two men starting from the same point begin walking in different directions. Their rates of travel are in the ratio 7:3. The slower walks towards the east. His faster companion walks to the south 10 pu and then turns towards the northeast and proceeds until both men meet. How many pu did each man walk?The author also discusses problem 6, the famous problem of a reed in a square pond:In the center of a square pond whose side measures 10 ch'ih grows a cattail whose top reaches 1 ch'ih above the water level. If we pull the reed toward the bank, its top becomes even with the waters surface. What is the depth of the pond and the length of the plant?As the author observes, this problem is very similar to a much later problem of Bh\=askara, where even the ratios involved are the same:In a certain lake, swarming with red geese, the tip of a bud of a lotus was seen a span (9 inches) above the surface of the water. Forced by the wind, it gradually advanced and was submerged at a distance of two cubits (approximately 40 inches). Compute quickly, mathematician, the depth of the pond.The question of Chinese influence on Indian mathematicians is still unsettled. One can't but wonder how the Chinese became so amazingly successful with the Chi-Chü method. The author mentions the possibility that familiarity with the tangram exercises may have contributed to their skill. Excellent article. Reprinted in Swetz, Frank J., From Five Fingers to Infinity. Closely related topics: The Chiu Chang Suan Shu (Nine Chapters on the Mathematical Art) and The Tangrams.
Taussky, Olga. From Pythagoras' theorem via sums of squares to celestial mechanics. Math. Intelligencer 10 (1988), no. 1, 52--55. (Reviewer: \v Stefan Porubsk\'y.) SC: 01-01 (01A99), MR: 89e:01002.
The author discusses parameterization of Pythagorean triangles, the law of quadratic reciprocity, representation of numbers in a fixed finite number of sums of squares numbers, quadratic forms, and connections with the complex numbers, quaternions, and Cayley numbers. The author tells that H. Levy and E. Isaacson observed the law of quadratic reciprocity in the study of water waves on a sloping beach (if sound waves behaved in an analogous way, would there be an applications in acoustics?). We see a surprising application of the parameterization of Pythagorean triangles in astronomy: E. Stiefel found observed that a straight line u1=c in the parameter plane (u1,u2) gives us triples (x,y,r) corresponding to a parabola, and if one moves along this line at a constant rate, one moves in a parabolic path according to Kepler's second law. Closely related topics: Imaginary and Complex Numbers, Number Theory, Algebra, Acoustics, and Astronomy.