Paper by Martin L. Demaine

Reference:

Erik D. Demaine, Martin L. Demaine, Vi Hart, Gregory N. Price, and Tomohiro Tachi, “(Non)existence of Pleated Folds: How Paper Folds Between Creases”, in Abstracts from the 7th Japan Conference on Computational Geometry and Graphs (JCCGG 2009), Kanazawa, Ishikawa, Japan, November 11–13, 2009, to appear.

Abstract:

We prove that the pleated hyperbolic paraboloid, a familiar origami model known since 1927, in fact cannot be folded with the standard crease pattern in the standard mathematical model of zero-thickness paper. In contrast, we show that the model can be folded with additional creases, suggesting that real paper “folds” into this model via small such creases. We conjecture that the circular version of this model, consisting of concentric circular creases, also folds without extra creases.

At the heart of our results is a new structural theorem characterizing uncreased intrinsically flat surfaces—the portions of paper between the creases. Differential geometry has much to say about the local behavior of such surfaces when they are sufficiently smooth, e.g., that they are torsal ruled. But this classic result is simply false in the context of the whole surface. Our structural characterization tells the whole story, and even applies to surfaces with discontinuities in the second derivative. We use our theorem to prove fundamental properties about how paper folds, for example, that straight creases on the piece of paper must remain piecewise-straight by folding.

Comments:

The full paper is available as arXiv:0906.4747.

Length:

The abstract is 2 pages.

Availability:

The abstract is available in PostScript (2268k), gzipped PostScript (1480k), and PDF (1484k).

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