Die Jakobsleiter ("Jacob's Ladder") is an oratorio by Arnold Schoenberg that marks his transition from a contextual or free atonality to the twelve-tone technique anticipated in the oratorio's use of hexachords. Though ultimately unfinished by Schoenberg the piece was prepared for performance by Schoenberg student Winfried Zillig at the request of Gertrude Schoenberg.
Emma Nevada (née Wixom) (7 February 1859 – 20 June 1940) was an American operatic soprano particularly known for her performances in operas by Bellini and Donizetti and the French composers Ambroise Thomas, Charles Gounod, and Léo Delibes.
 Considered one of the finest coloratura sopranos of the late 19th and early 20th centuries, her most famous roles were Amina in "La sonnambula", and the title roles in "Lakmé", "Mignon", "Mireille", and "Lucia di Lammermoor.
Style and Idea: Selected Writings of Arnold Schoenberg (in German: "Stil und Gedanke") is the name for a published collection of essays, articles and sketches by Arnold Schoenberg, that has appeared in various forms.
This is list of operas and operettas written by the French composer Léo Delibes (1836–1891).
The Second Viennese School (German: Zweite Wiener Schule, Neue Wiener Schule ) is the group of composers that comprised Arnold Schoenberg and his pupils and close associates in early 20th century Vienna, where he lived and taught, sporadically, between 1903 and 1925.
 Their music was initially characterized by late-Romantic expanded tonality and later, following Schoenberg's own evolution, a totally chromatic expressionism without firm tonal centre, often referred to as atonality; and later still, Schoenberg's serial twelve-tone technique.
 Though this common development took place, it neither followed a common time-line nor a cooperative path.
 Likewise, it was not a direct result of Schoenberg's teaching—which, as his various published textbooks demonstrate, was highly traditional and conservative.
 Schoenberg's textbooks also reveal that the Second Viennese School spawned not from the development of his serial method, but rather from the influence of his creative example.
The Arnold Schoenberg Choir (German: "Arnold Schoenberg Chor" ) is a Viennese/Austrian choir which was founded 1972 by Erwin Ortner, who is still its artistic director.
 The choir has a high reputation both among conductors and among critics and the musical scene in general.
 All members of the choir have broad experience and expertise in vocal music; most of them have graduated from or are currently studying at the Vienna University of Music and Performing Arts.
 The choir is named after Viennese composer Arnold Schoenberg.
Arnold Franz Walter Schoenberg or Schönberg ( ; ] ; 13 September 187413 July 1951) was an Austrian composer, music theorist, and painter.
 He was associated with the expressionist movement in German poetry and art, and leader of the Second Viennese School.
 With the rise of the Nazi Party, Schoenberg's works were labelled degenerate music, because they were modernist, atonal and what even Paul Hindemith called "sonic orgies" and "decadent intellectual efforts".
 He emigrated to the United States of America in 1934.
Clément Philibert Léo Delibes (] ; 21 February 1836 – 16 January 1891) was a French composer of the Romantic era (1815–1910), who specialised in ballets, operas, and other works for the stage.
 His most notable works include the ballets "Coppélia" (1870) and "Sylvia" (1876), as well as the operas "Le roi l'a dit" (1873) and "Lakmé" (1883).
Balanchine's had previously made a "pas de deux" to music from Léo Delibes' "Sylvia" in 1950; he expanded this into a divertissement in 1965.
 The final version uses music from Delibes' ballets "La source" and "Sylvia" and choreography from the earlier pas de deux and divertissement.
"La source (The Spring)" is a ballet in three acts/four scenes with a score composed by Léo Delibes and Ludwig Minkus (Minkus: Act I & Act III-Scene 2/Delibes: Act II & Act III-Scene 1) which was premiered in 1866 with choreography by Arthur Saint-Léon.
 In 1878 in Vienna it was called "Naïla, die Quellenfee" ("Naïla, the Waternymph").

Question: What kind of musician does Arnold Schoenberg and Léo Delibes have in common?
Answer: composer