Don Giovanni is an opera in two acts with music by Wolfgang Amadeus Mozart and Italian libretto by Lorenzo Da Ponte. It is based on the legends of Don Juan, a fictional libertine and seducer, by Spanish writer Tirso de Molina, it was premiered by the Prague Italian opera at the National Theater, now called the Estates Theatre, on 29 October 1787. Da Ponte's libretto was billed as a dramma giocoso, a common designation of its time that denotes a mixing of serious and comic action. Mozart entered the work into his catalogue as an opera buffa. Although sometimes classified as comic, it blends comedy and supernatural elements. Don Giovanni is regarded as one of Mozart’s supreme achievements and one of the greatest operas of all time, it has proved a fruitful subject for writers and philosophers. A staple of the standard operatic repertoire, it is ninth on the Operabase list of the most-performed operas of the 2018-19 season; the opera was commissioned as a result of the overwhelming success of Mozart's trip to Prague in January and February 1787.

The subject matter may have been chosen in consideration of the long history of Don Juan operas in Prague. The libretto of Lorenzo Da Ponte was based on a libretto by Giovanni Bertati for the opera Don Giovanni Tenorio, first performed in Venice early in 1787, although Da Ponte was loath to admit this in memoirs written decades later; some of the most important elements that he copied were the idea of opening the drama with the murder of the Commendatore and the lack of a specification of Seville as the setting, customary in the tradition of Don Juan dramas since the appearance of the prototype Don Juan drama El burlador de Sevilla by Tirso de Molina, written in the early 17th century. For Bertati, the setting was Villena, whereas Da Ponte's libretto only specifies a "city in Spain". According to some sources, Giacomo Casanova assisted in the writing. Don Giovanni was to have been performed on 14 October 1787 for a visit to Prague of the Archduchess Maria Theresa of Austria, niece of the Emperor Joseph II, her new husband, Prince Anthony of Saxony.

The score was completed on 28 or 29 October 1787 after Da Ponte was recalled to Vienna to work on another opera. Reports about the last-minute completion of the overture conflict. More it was completed the day before, in light of the fact that Mozart recorded the completion of the opera on 28 October; the score calls for double woodwinds, two horns, two trumpets, three trombones, basso continuo for the recitatives, the usual string section. The composer specified occasional special musical effects. For the ballroom scene at the end of the first act, Mozart calls for two onstage ensembles to play separate dance music in synchronization with the pit orchestra, each of the three groups playing in its own metre, accompanying the dancing of the principal characters. In act 2, Giovanni is seen to play the mandolin, accompanied by pizzicato strings. In the same act, two of the Commendatore's interventions are accompanied by a wind chorale of oboes, clarinets and trombones; the opera was first performed on 29 October 1787 in Prague under its full title of Il dissoluto punito ossia il Don Giovanni – Dramma giocoso in due atti.

The work was rapturously received, as was true of Mozart's work in Prague. The Prager Oberpostamtzeitung reported, "Connoisseurs and musicians say that Prague has never heard the like," and "the opera … is difficult to perform." The Provincialnachrichten of Vienna reported, "Herr Mozart conducted in person and was welcomed joyously and jubilantly by the numerous gathering." Mozart supervised the Vienna premiere of the work, which took place on 7 May 1788. For this production, he wrote two new arias with corresponding recitatives – Don Ottavio's aria "Dalla sua pace", Elvira's aria "In quali eccessi... Mi tradì quell'alma ingrata" – and the duet between Leporello and Zerlina "Per queste tue manine", he made some cuts in the Finale in order to make it shorter and more incisive, the most important of, the section where Anna and Ottavio, Elvira and Masetto, Leporello reveal their plans for the future. In order to connect "Ah, certo è l'ombra che l'incontrò" directly to the moral of the story "Questo è il fin di chi fa mal", Mozart composed a different version of "Resti dunque quel birbon fra Proserpina e Pluton!".

These cuts are seldom performed in theatres or recordings. The opera's final ensemble was omitted until the early 20th century, a tradition that began early on. According to the 19th-century Bohemian memoirist Wilhelm Kuhe, the final ense

GP Investments, is a leading alternative investment firm in Latin America with a strong presence in asset management, principally private equity funds. The firm's shares are listed on the Luxembourg Stock Exchange and trade on BM&FBovespa, the Brazilian Stock Exchange, via Brazilian Depositary Receipts. Since its foundation in 1993, GP Investments has raised US$5 billion from investors worldwide and has completed investments in more than 50 companies in 15 different industries. GP Investments is based in Bermuda; the firm has offices in São Paulo, New York City, United States, Zurich, Switzerland. GP Investments was founded in 1993 to focus on investments in Latin America, what was at that point a nascent market in private equity. In 1994, GP raised its first investment fund with US$500 million of investor capital which it followed up with its US$800 million successor fund, GP Capital Partners II, in 1997. In 2001, the firm completed fundraising for its first local private equity fund raising R$130 million to focus on technology investments.

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Donald Dines Wall was a mathematician working on number theory. He obtained his Ph. D. on normal numbers from University of California, Berkeley in 1949, where his adviser was Derrick Henry Lehmer. His better known papers include the first modern analysis of Fibonacci sequence modulo a positive integer. Drawing on Wall's work, Zhi-Hong Sun and his twin brother Zhi-Wei Sun proved a theorem about what are now known as the Wall–Sun–Sun primes that guided the search for counterexamples to Fermat's last theorem. Wall was born in Kansas City, Missouri on August 13, 1921 to Donald F. Wall and Mary Wooldridge; the family lived in Texas as he was growing up. In 1933, they moved to Whittier, California in 1936 to Santa Barbara, where he graduated from high school in 1938, he joined the Delta Sigma Phi fraternity. In April 1940 he had a successful operation to remove a brain tumor at UC Hospital in San Francisco; the surgeon was Howard C. Naffziger, who served on the board of Regents of the University of California.

He and Naffziger kept in touch for many years afterwards. He graduated from UCLA with a B. A. in Mathematics in the spring of 1944. After graduation he took a full-time job with Douglas Aircraft but continued in graduate school at UCLA. In 1946 he received an M. A. in mathematical statistics from UCLA. In the same year he passed the first three of eight actuarial exams. In 1947, he moved to Connecticut to work for the Aetna Life Insurance Company, he taught an evening math class at Trinity College. In the fall of 1947, he returned to graduate school at Harvard University, where he became interested in number theory, he took a class at Massachusetts Institute of Technology. In June 1948 he returned to California to complete his Ph. D. at UC Berkeley, where he taught classes as a teaching assistant. In 1949 he was awarded his Ph. D. in normal numbers from UC Berkeley. In fall of 1949 he and his family moved to Santa Barbara where he took a job as instructor in mathematics at Santa Barbara College of the University of California.

He taught general astronomy as well as number theory and other math courses. After two years, he was promoted to assistant professor. In 1950, he taught a course in computer mathematics at Naval Air Station Point Mugu, where computers were being developed for calculating missile trajectories. From his work at Pt Mugu, he was recruited by IBM to work as an Applied Science Representative starting July 1951 in Los Angeles. In 1956, he became IBM's Education Coordinator for the west coast, he traveled to interested universities in the western US to give them details of a program developed by the UCLA Anderson School of Management about the use of computers in business. In 1958, he moved to White Plains, New York and continued working at IBM until his retirement in 1982. ———. "The accuracy of the root-squaring method for solving equations", J. Math. and Phys. 26: 156–164. ———, Normal numbers, Berkeley: Ph. D. thesis, Univ. California. ———, "The order of an iteration formula", Math. Tables Aids Comput. 10: 167–168.

———, "Fibonacci Series Modulo m", American Mathematical Monthly, 67: 525–532, doi:10.2307/2309169 ———, "Moments of a Function on the Cantor Set", American Mathematical Monthly, 68: 460–461, doi:10.2307/2311100 Donald Dines Wall at the Mathematics Genealogy Project