Article: The modern concept of an abstract group developed out of several fields of mathematics. The original motivation for group theory was the quest for solutions of polynomial equations of degree higher than 4. The 19th-century French mathematician Evariste Galois, extending prior work of Paolo Ruffini and Joseph-Louis Lagrange, gave a criterion for the solvability of a particular polynomial equation in terms of the symmetry group of its roots (solutions). The elements of such a Galois group correspond to certain permutations of the roots. At first, Galois' ideas were rejected by his contemporaries, and published only posthumously. More general permutation groups were investigated in particular by Augustin Louis Cauchy. Arthur Cayley's On the theory of groups, as depending on the symbolic equation n = 1 (1854) gives the first abstract definition of a finite group.

Question: What modern concept was created from many fields of mathematics?
Ans: abstract group

Article: In the spring of 1834, Chopin attended the Lower Rhenish Music Festival in Aix-la-Chapelle with Hiller, and it was there that Chopin met Felix Mendelssohn. After the festival, the three visited Dusseldorf, where Mendelssohn had been appointed musical director. They spent what Mendelssohn described as "a very agreeable day", playing and discussing music at his piano, and met Friedrich Wilhelm Schadow, director of the Academy of Art, and some of his eminent pupils such as Lessing, Bendemann, Hildebrandt and Sohn. In 1835 Chopin went to Carlsbad, where he spent time with his parents; it was the last time he would see them. On his way back to Paris, he met old friends from Warsaw, the Wodzinskis. He had made the acquaintance of their daughter Maria in Poland five years earlier, when she was eleven. This meeting prompted him to stay for two weeks in Dresden, when he had previously intended to return to Paris via Leipzig. The sixteen-year-old girl's portrait of the composer is considered, along with Delacroix's, as among Chopin's best likenesses. In October he finally reached Leipzig, where he met Schumann, Clara Wieck and Felix Mendelssohn, who organised for him a performance of his own oratorio St. Paul, and who considered him "a perfect musician". In July 1836 Chopin travelled to Marienbad and Dresden to be with the Wodzinski family, and in September he proposed to Maria, whose mother Countess Wodzinska approved in principle. Chopin went on to Leipzig, where he presented Schumann with his G minor Ballade. At the end of 1836 he sent Maria an album in which his sister Ludwika had inscribed seven of his songs, and his 1835 Nocturne in C-sharp minor, Op. 27, No. 1. The anodyne thanks he received from Maria proved to be the last letter he was to have from her.

Question: Who did Chopin attend the Lower Rhenish Music Festival with?
Ans: Hiller

Article: On May 16, rescue groups from South Korea, Japan, Singapore, Russia and Taiwan arrived to join the rescue effort. The United States shared some of its satellite images of the quake-stricken areas with Chinese authorities. During the weekend, the US sent into China two U.S. Air Force C-17's carrying supplies, which included tents and generators. Xinhua reported 135,000 Chinese troops and medics were involved in the rescue effort across 58 counties and cities.

Question: How many Chinese troops and medics were involved in the relief efforts?
Ans: 135,000

Article: Meditation was an aspect of the practice of the yogis in the centuries preceding the Buddha. The Buddha built upon the yogis' concern with introspection and developed their meditative techniques, but rejected their theories of liberation. In Buddhism, mindfulness and clear awareness are to be developed at all times; in pre-Buddhist yogic practices there is no such injunction. A yogi in the Brahmanical tradition is not to practice while defecating, for example, while a Buddhist monastic should do so.

Question: In Buddhism, what must be developed at all times?
Ans:
mindfulness and clear awareness