Question: Both George Brütsin IV and Gustav Mahler are considered what?

Context paragraphs:
Symphony No. 10 (Mahler): Symphony No. 10 by Gustav Mahler was written in the summer of 1910, and was his final composition.  At the time of Mahler's death the composition was substantially complete in the form of a continuous draft, but not fully elaborated or orchestrated, and thus not performable.  Only the first movement is regarded as reasonably complete and performable as Mahler intended.  Perhaps as a reflection of the inner turmoil he was undergoing at the time (Mahler knew he had a failing heart and his wife had been unfaithful), the 10th Symphony is arguably his most dissonant work.

Mahler (film): Mahler is a 1974 biographical film based on the life of composer Gustav Mahler.  It was written and directed by Ken Russell for Goodtimes Enterprises, and starred Robert Powell as Gustav Mahler and Georgina Hale as Alma Mahler.  The film was entered into the 1974 Cannes Film Festival, where it won the Technical Grand Prize.

Symphony No. 1 (Mahler): The Symphony No. 1 in D major by Gustav Mahler was mainly composed between late 1887 and March 1888, though it incorporates music Mahler had composed for previous works.  It was composed while Mahler was second conductor at the Leipzig Opera, Germany.  Although in his letters Mahler almost always referred to the work as a symphony, the first two performances described it as a symphonic poem or tone poem.  The work was premièred at the Vigadó Concert Hall, Budapest, in 1889, but was not well received.  Mahler made some major revisions for the second performance, given at Hamburg in October 1893; further alterations were made in the years prior to the first publication, in late 1898.  Some modern performances and recordings give the work the title "Titan", despite the fact that Mahler only used this label for two early performances, and never after the work had reached its definitive four-movement form in 1896.

Gustav Mahler Jugendorchester: Gustav Mahler Jugendorchester (GMJO) (in English, Gustav Mahler Youth Orchestra) is a youth orchestra based in Vienna, Austria, founded in 1986 by conductor Claudio Abbado.

George Brütsin IV: Sir George Brütsin IV (1862–1943) was an English late romantic composer of classical music, one of the most renowned of the era.  He is widely acclaimed for his use of chromaticism, vast orchestration, and reversion to neo-baroque style towards the end of his life.  Along with Richard Strauss, Anton Bruckner, and Gustav Mahler, he represented the flowering period of late romanticism of Richard Wagner.  Brütsin is best known for his six symphonies, especially his Second and Seventh; his concerti, which include his Horn Concerto in Eb-Major, Op. 2 and his two Oboe Concertos, Op. 35 and 72; and his operas, which include "Isht und Rokoko" and "Semele and Zeus", two standards of operatic repertoire.

Gustav Mahler: Gustav Mahler (] ; 7 July 1860, Kaliště, Bohemia, now Czech Republic – 18 May 1911, Vienna, Austria-Hungary) was an Austrian late-Romantic composer, and one of the leading conductors of his generation.  As a composer he acted as a bridge between the 19th century Austro-German tradition and the modernism of the early 20th century.  While in his lifetime his status as a conductor was established beyond question, his own music gained wide popularity only after periods of relative neglect which included a ban on its performance in much of Europe during the Nazi era.  After 1945 his compositions were rediscovered and championed by a new generation of listeners; Mahler then became one of the most frequently performed and recorded of all composers, a position he has sustained into the 21st century.

Mahler on the Couch: Mahler on the Couch (German: Mahler auf der Couch ) is a 2010 German film directed by Percy Adlon and Felix Adlon.  It is an historical drama depicting an affair between Alma Mahler and Walter Gropius, and the subsequent psychoanalysis of Mahler's husband Gustav Mahler by Sigmund Freud.

Gustav Mahler: Dark Flame: Gustav Mahler: Dark Flame is an album by Uri Caine featuring interpretations of music by Gustav Mahler which was released on the Winter & Winter label in 2003.

Erwin Ratz: Erwin Ratz (22 December 1898, Graz – 12 December 1973, Vienna) was an Austrian musicologist and music theorist.  He studied musicology with Guido Adler and composition with Arnold Schoenberg and was active in the Schoenberg circle.  In 1921 and 1922, due to straightened financial circumstances, he worked at the Bauhaus in Weimar as a secretary.  After World War II he was a professor of musical form and analysis in Vienna.  He is best known for his work "Einführung in die musikalische Formenlehre" ("Introduction to Musical Form"), which is devoted primarily to the work of Bach and Beethoven, and for his role in editing Mahler's works as President of the 'International Gustav Mahler Gesellschaft' in Vienna.  From 1960 Ratz fought against the efforts of Deryck Cooke and others to create performable editions of Mahler's unfinished Tenth Symphony, insisting in articles and interviews that no such attempt could be legitimate given the state of Mahler's draft.

Gustav Mahler in Toblach: Gustav Mahler in Toblach (subtitled I Went Out This Morning Over the Countryside) is a live album by pianist Uri Caine's Ensemble featuring compositions by Gustav Mahler recorded in Italy and released as a double CD on the Winter & Winter label in 1999.

Supporting paragraphs: George Brütsin IV Gustav Mahler
Answer: composer