{ "id": "1005.1033", "version": "v2", "published": "2010-05-06T16:26:45.000Z", "updated": "2015-12-17T15:29:03.000Z", "title": "Random Gaussian Tetrahedra", "authors": [ "Steven Finch" ], "comment": "18 pages", "categories": [ "math.PR", "math.MG" ], "abstract": "Given independent normally distributed points A,B,C,D in Euclidean 3-space, let Q denote the plane determined by A,B,C and D^ denote the orthogonal projection of D onto Q. The probability that the tetrahedron ABCD is acute remains intractible. We make some small progress in resolving this issue. Let Gamma denote the convex cone in Q containing all linear combinations A+r*(B-A)+s*(C-A) for nonnegative r, s. We compute the probability that D^ falls in (B+C)-Gamma to be 0.681..., but the probability that D^ falls in Gamma to be 0.683.... The intersection of these two cones is a parallelogram in Q twice the area of the triangle ABC. Among other issues, we mention the distribution of random solid angles and sums of these.", "revisions": [ { "version": "v1", "updated": "2010-05-06T16:26:45.000Z", "journal": null, "doi": null }, { "version": "v2", "updated": "2015-12-17T15:29:03.000Z" } ], "analyses": { "subjects": [ "60D05", "51M04", "51M25", "62H10", "62E15", "52B10", "52A38" ], "keywords": [ "random gaussian tetrahedra", "probability", "random solid angles", "gamma denote", "acute remains" ], "note": { "typesetting": "TeX", "pages": 18, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2010arXiv1005.1033F" } } }