All articles starting with S

Schumann-Heink Corona

Schumann-Heink Corona is a 122 km wide corona on Venus at 74.30°N, 214.50°E, IAU-approved in 1997, named for German singer Ernestine Schumann-Heink, formerly Schumann-Heink Patera.

Schunk GmbH

Schunk GmbH is a German technology group founded in 1913 in Heuchelheim near Gießen, working in carbon and ceramics materials, distinct from the gripper maker SCHUNK SE.

Schur complement

The Schur complement is a matrix constructed from a block matrix, equal to A22 − A21A11⁻¹A12, arising when one group of variables is eliminated from a linear system.

Schur decomposition

The Schur decomposition writes a square matrix A as A = UTU, with U unitary and T upper triangular; it exists for every square matrix and underlies the QR algorithm.

Schur functions

Schur functions are the holomorphic functions on the open unit disk bounded by one in modulus; Schur's 1917 paper associated each with a sequence of parameters.

Schur functor

A Schur functor is a polynomial construction on vector spaces indexed by a Young diagram, generalizing symmetric and exterior powers; it arose in Issai Schur's 1901 thesis.

Schur multiplier

The Schur multiplier of a group G is the abelian group H₂(G, ℤ), introduced by Issai Schur in 1904; it classifies central extensions of G and the obstruction to lifting projective representations.

Schur polynomial

A Schur polynomial is a symmetric homogeneous polynomial indexed by a partition, forming a basis of symmetric functions and serving as characters of irreducible representations of GL_n.

Schur–Weyl duality

Schur–Weyl duality, also called Frobenius–Schur duality, is a theorem in representation theory describing how the general linear group and the symmetric group act on tensor powers of a vector space.

Schur's lemma

Schur's lemma is a fundamental result of representation theory, proved by Issai Schur in 1907, stating that a homomorphism between irreducible representations is either zero or an isomorphism.

Schur's theorem (Ramsey theory)

Schur's theorem is a 1916 result in Ramsey theory: every k-coloring of 1 through n contains same-colored x, y, z with x + y = z.

Schuster

Schuster is a Swedish Tables (backgammon-family) race game played in Sweden by women, on a horseshoe track with 15 pieces and two dice; the name means shoemaker, the winner 'gör schuster'.

Schuster (lunar crater)

Schuster is a 100.08-km-wide impact crater on the Moon's far side at 4.44°N, 146.42°E, named in 1970 for Sir Arthur Schuster, British mathematician and physicist (1851-1934).

Schütte

Schütte (Alfred H. Schütte GmbH & Co. KG) is a German family-owned machine tool manufacturer in Cologne, founded in 1880, producing multi-spindle automatic lathes and 5-axis CNC grinding machines.

Schutzhund (German for protection dog), now IGP, is a FCI-recognized dog sport from early-1900s Germany with tracking, obedience, and protection phases, created to test German Shepherd breeding suitability.

Schutzstaffel

Schutzstaffel (SS), Protection Squadrons: Nazi Party paramilitary organization founded by Hitler in 1925 as his bodyguard, turned into the elite police, camp, and Holocaust apparatus under Himmler; banned and declared criminal in 1945.

Schuurs-Hoeijmakers syndrome

Schuurs-Hoeijmakers syndrome, or PACS1-related neurodevelopmental disorder (OMIM 615009), is an ultra-rare autosomal dominant disorder caused mainly by the de novo PACS1 c.607C>T p.Arg203Trp variant, causing intellectual disability, speech delay, distinctive facial features, and seizures.

Schuyler Colfax

Schuyler Colfax (1823–1885), Indiana Republican, Speaker of the U.S. House (1863–1869) and 17th Vice President under Grant (1869–1873); first Speaker to become VP, ruined by the 1872 Crédit Mobilier scandal.

Schuyler family

Schuyler family, Dutch-American lineage of Albany, New York, founded by Philip Pieterse Schuyler; produced mayors, Major General Philip Schuyler, the Hamilton-famous Schuyler sisters, and the Black Hudson River Schuylers.

Schuyler Fisk

Schuyler Elizabeth Fisk (born 1982), American actress and singer-songwriter, daughter of Sissy Spacek and Jack Fisk; known for The Baby-Sitters Club, Orange County, Restless, Sam & Kate, and albums The Good Stuff and Blue Ribbon Winner.

Schuyler Grant

Schuyler Grant (Schuyler DeBarthe Ranson Grant, born 1971) is an American actress who played Diana Barry in the Anne of Green Gables films, and a yoga teacher who founded Kula Yoga Project and co-created Wanderlust.

Schuylkill County

Schuylkill County, Pennsylvania: county established March 1, 1811, named for the Schuylkill River; 67 municipalities, 143,049 people (2020), anthracite coal heritage, Pottsville its main town.

Schuylkill notes

Schuylkill notes: small folded conspiracy-theory notes, also called the Schuylkill Notes mystery papers, found in sealed food packaging, clothing pockets, and on Pennsylvania trails since about 2019; authorship unknown, FDA and FBI attention, insertion replicated in-store.

Schuylkill River

The Schuylkill River (Dutch "hidden river") is a 130-mile Pennsylvania tributary of the Delaware River, the coal-carrying Schuylkill Navigation's route, once heavily polluted, now a restored drinking-water and recreation river.

Schw. augsburg

Schw. Augsburg (TSV 1847 Schwaben Augsburg), Augsburg sports club; football section 1899; Oberliga Süd member; 1969 merger created FC Augsburg; now Regionalliga Bayern, lilac-white, Rosenaustadion.

Oct 22, 2026

Schwank

A Schwank (plural Schwänke) is a short German humorous narrative, often crudely comic, in prose or verse, used since the 15th century, and later also a comic stage play.

Schwann cell

Schwann cell: PNS glial cell (Theodor Schwann, 1839) forming myelin sheaths of peripheral axons, one internode per cell, derived from neural crest; transdifferentiates into repair cells after injury and is used in nerve repair and spinal cord injury trials.

Schwannoma

Schwannoma, also called neurilemmoma, is a usually benign nerve sheath tumor arising from Schwann cells, the most common peripheral nerve tumor in adults, often on the vestibular nerve.

Schwartz & Sandy's

Schwartz & Sandy's was a cocktail lounge and restaurant in Los Angeles's Franklin Village, opened by Tom Schwartz and Tom Sandoval in 2022 and closed in December 2024.