{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.ellipse","code":"thing-q40112","url":"https://ver.cy/models/thing/q40112/","name":"ellipse","alternateNames":["Golden ellipse","Steiner ellipse","Tissot's indicatrix","great ellipse","inellipse"],"kind":"thing","status":"published","version":"0.2.0-wave.2","language":"en","classifiers":{"family":"Thing Registry","category":"Cross-cutting context","entryKind":"thing","plane":"XCT","domain":["XCT.QLT"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"A closed plane curve consisting of all points whose distances to two fixed points, the foci, sum to a constant, forming an elongated circle characterised by its major and minor axes and eccentricity, obtained as a conic section and appearing as planetary orbits, in special forms such as the Steiner ellipse of a triangle, inellipses, the great ellipse on a spheroid, the Tissot indicatrix of map distortion and the golden ellipse; the ellipse is fundamental in geometry, astronomy, optics and engineering.","purpose":"Let an agent explain the ellipse and its properties and equations, support calculations of area, perimeter and parameters, describe applications in orbits, optics and cartography, and support learning.","scope":{"in":[],"out":[],"boundaries":[]},"distinguishingFeatures":["Two foci","Conic section","Eccentricity","Orbital significance"],"structure":{"bundles":[{"id":"understand","name":"Understand","description":"What an ellipse is.","layers":[{"id":"definition","name":"Definition","description":"Definition and properties.","findings":[{"id":"definition-finding","name":"Definition","description":"Definition.","questions":[{"text":"How is an ellipse defined by foci, as a conic section and by its equation, and what are its axes and eccentricity?","kind":"definition"},{"text":"Which entry fits conic sections?","kind":"action"}]}]},{"id":"special","name":"Special","description":"Special ellipses.","findings":[{"id":"special-finding","name":"Special","description":"Special.","questions":[{"text":"What are Steiner ellipses, inellipses, great ellipses, the Tissot indicatrix and the golden ellipse?","kind":"definition"},{"text":"Which entry fits a specific special ellipse?","kind":"action"}]}]}]},{"id":"compute","name":"Compute","description":"Calculations.","layers":[{"id":"calculate","name":"Calculate","description":"Area, perimeter and parameters.","findings":[{"id":"calculate-finding","name":"Calculate","description":"Calculation.","questions":[{"text":"What are the area, approximate perimeter, foci and eccentricity of this ellipse?","kind":"action"},{"text":"Which entry fits elliptic integrals?","kind":"action"}]}]},{"id":"construct","name":"Construct","description":"Construction and drawing.","findings":[{"id":"construct-finding","name":"Construct","description":"Construction.","questions":[{"text":"How can an ellipse be constructed with string, trammel or software?","kind":"action"},{"text":"Which entry fits geometric construction?","kind":"action"}]}]}]},{"id":"apply","name":"Apply","description":"Applications.","layers":[{"id":"orbits","name":"Orbits","description":"Orbits.","findings":[{"id":"orbits-finding","name":"Orbits","description":"Orbits.","questions":[{"text":"Why are planetary orbits ellipses, and how do Kepler laws use ellipse properties?","kind":"provenance"},{"text":"Which entry fits orbital mechanics?","kind":"action"}]}]},{"id":"other","name":"Other","description":"Optics, engineering and maps.","findings":[{"id":"other-finding","name":"Other","description":"Other.","questions":[{"text":"How are ellipses used in reflectors, gears, architecture and map distortion analysis?","kind":"provenance"},{"text":"Which entry fits a specific application?","kind":"action"}]}]}]},{"id":"learn","name":"Learn","description":"History and teaching.","layers":[{"id":"history","name":"History","description":"History.","findings":[{"id":"history-finding","name":"History","description":"History.","questions":[{"text":"How did the ellipse develop from Apollonius through Kepler to modern geometry?","kind":"provenance"},{"text":"Which references are standard?","kind":"provenance"}]}]},{"id":"teach","name":"Teach","description":"Teaching.","findings":[{"id":"teach-finding","name":"Teach","description":"Teaching.","questions":[{"text":"How can ellipses be taught with string constructions and orbits?","kind":"action"},{"text":"Which misconceptions arise?","kind":"provenance"}]}]}]}]},"agentConduct":{"may":["Define an ellipse and compute its properties such as axes, foci and eccentricity.","State formulas and approximations, such as for the perimeter, with their accuracy.","Draw and fit ellipses to data it is authorized to analyse."],"mustNot":["Present an approximate perimeter formula as exact.","Confuse an ellipse with an oval or egg shape in technical work.","Fit ellipses to data in a way that overstates their precision.","Attribute a theorem or construction to the wrong mathematician."],"requiresHuman":["Using an elliptical fit for decisions about safety, such as orbits or tolerances."]},"ethics":{"considerations":["Misstated mathematics in engineering or navigation can have real consequences.","Credit for discoveries matters to their authors and traditions."],"affectedParties":["Students","Engineers","Users of results"]},"owners":{"steward":"Nobody: a mathematical object held in common.","roles":[],"masterSystems":[]},"relations":[{"target":"Q1047694","type":"parent","note":"registry parent class"},{"target":"Q124255","type":"parent","note":"registry parent class"},{"target":"Q17099260","type":"parent","note":"registry parent class"},{"target":"Q2983648","type":"parent","note":"registry parent class"},{"target":"Q594135","type":"parent","note":"registry parent class"},{"target":"Q78145859","type":"parent","note":"registry parent class"},{"target":"conic section","type":"related","note":"category"},{"target":"hypotrochoid","type":"related","note":"category"},{"target":"plane","type":"related","note":"the plane containing the ellipse"},{"target":"cylinder","type":"related","note":"ellipses as cylinder sections"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.ellipse","Wikidata: Q40112 (https://www.wikidata.org/wiki/Q40112)"]},"properties":{"applicability":"not-applicable","items":[]},"recognition":{"applicability":"optional","items":["Constant sum of distances to two foci","Major and minor axes, eccentricity","A circle is the special case with coincident foci; an oval is any egg-like shape","An elongated circle."]},"capabilities":{"applicability":"required","items":["explain properties and equations","support calculations","describe applications","support learning"]},"hazards":{"applicability":"required","items":["Confusing ellipse and oval","Perimeter approximation errors","Axis and eccentricity confusion"]},"interfaces":{"applicability":"required","items":["Mathematical conventions","Cartographic distortion analysis conventions","No regulation"]},"context":{"applicability":"required","items":["Closed curve with constant sum of focal distances.","ellipses by eccentricity","Steiner and other triangle ellipses","inellipses and circumellipses","great ellipses on spheroids","ellipses in map distortion analysis"]}},"sources":[{"title":"Wikidata item Q40112: ellipse","url":"https://www.wikidata.org/wiki/Q40112","note":"identity and sense of the item"},{"title":"Wikipedia: Ellipse","url":"https://en.wikipedia.org/wiki/Ellipse","note":"general description of the item"}],"openQuestions":["Should conic sections be a separate entry?","How should geometry resources be linked?","How should orbital mechanics be linked?"],"resources":{"spec":"/models/things/publications/thing-q40112/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q40112/spec.json"],"providers":["Claude"],"researchStatus":"unreviewed","generatedAt":"2026-09-12T04:08:37Z","builder":"tools/build_cards.py@1.0.0"},"completeness":{"sections":{"classifiers":"filled","whatItIs":"filled","purpose":"filled","distinguishingFeatures":"filled","structure":"filled","agentConduct":"filled","ethics":"filled","owners":"filled","relations":"filled","interaction.identity":"filled","interaction.properties":"not-applicable","interaction.recognition":"filled","interaction.capabilities":"filled","interaction.hazards":"filled","interaction.interfaces":"filled","interaction.context":"filled","sources":"filled"},"notes":{"_gate":"Published through the thing publication gate 1.0 on 2026-10-06T19:51:59+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass","interaction.properties":"Plane XCT: no invented physical properties."},"score":1.0}}