Proprietas Eulerana
Proprietas Eulerana, vel numerus Euleranus et proprietas Eulerana–Poincareana, in mathematica et praecipue in topologia algebraica et combinatoricis polyhedralicis est invarians topologicus, numerus qui formam vel structuram cuiusdam spatii topologici describit, modo per quem inflectatur omisso. Usitate per  (chi, minorem litteram Graecam) scribitur.

Notae

Bibliographia 
 Eulerus, Leonhardus. 1758. "Elementa doctrinae solidorum." Novi Commentarii Academiae Scientiarum Petropolitanae 109–140. Textus.
 Flegg, H. Graham. 2001. From Geometry to Topology. Mineolae Novi Eboraci: Dover. ISBN 0486419614.
 Friedman, Michael. 2018. A History of Folding in Mathematics: Mathematizing the Margins. Birkhäuser. Science Networks: Historical Studies 59. ISBN 978-3-319-72486-7. .
 Gottlieb, Daniel Henry. 1975. "Fibre bundles and the Euler characteristic." Journal of Differential Geometry 10 (1): 39–48. . PDF.
 Leinster, Tom. 2008. "The Euler characteristic of a category." Documenta Mathematica 13: 21–49. PDF.
 Richeson, David S. 2008. Euler's Gem: The Polyhedron Formula and the Birth of Topology. Princeton Novae Caesareae: Princeton University Press. ISBN 9780691126777, ISBN 0691126771.
 Spanier, Edwin Henry. 1982. Algebraic Topology. Springer. ISBN 978-0-387-94426-5. Google Books.

 Algebra homologica
 Renatus Cartesius
 Leonardus Eulerus
 Numerus Euleri
 Sphaera

Nexus externi 
Documentum animatum per geometriam sphaericam monstratum.

Leonhardus Eulerus
Topologia algebraica