Conductor

Conductor or conduction may refer to:

In physics:

In mathematics:

Conductor (class field theory)

In algebraic number theory, the conductor of a finite abelian extension of local or global fields provides a quantitative measure of the ramification in the extension. The definition of the conductor is related to the Artin map.

Local conductor

Let L/K be a finite abelian extension of non-archimedean local fields. The conductor of L/K, denoted , is the smallest non-negative integer n such that the higher unit group

is contained in N_L/K(L^×), where N_L/K is field norm map and is the maximal ideal of K. Equivalently, n is the smallest integer such that the local Artin map is trivial on . Sometimes, the conductor is defined as where n is as above.

The conductor of an extension measures the ramification. Qualitatively, the extension is unramified if, and only if, the conductor is zero, and it is tamely ramified if, and only if, the conductor is 1. More precisely, the conductor computes the non-triviality of higher ramification groups: if s is the largest integer for which the "lower numbering" higher ramification group G_s is non-trivial, then , where η_L/K is the function that translates from "lower numbering" to "upper numbering" of higher ramification groups.

Underground Railroad

The Underground Railroad was a network of secret routes and safe houses used by 19th-century enslaved people of African descent in the United States in efforts to escape to free states and Canada with the aid of abolitionists and allies who were sympathetic to their cause. The term is also applied to the abolitionists, both black and white, free and enslaved, who aided the fugitives. Various other routes led to Mexico or overseas. An "Underground Railroad" running south toward Florida, then a Spanish possession, existed from the late 17th century until shortly after the American Revolution. However, the network now generally known as the Underground Railroad was formed in the early 19th century, and reached its height between 1850 and 1860. One estimate suggests that by 1850, 100,000 slaves had escaped via the "Railroad".

British North America (present-day Canada), where slavery was prohibited, was a popular destination, as its long border gave many points of access. Most former slaves settled in Ontario. More than 30,000 people were said to have escaped there via the network during its 20-year peak period, although U.S. Census figures account for only 6,000. Numerous fugitives' stories are documented in the 1872 book The Underground Railroad Records by William Still, an abolitionist who then headed the Philadelphia Vigilance Committee.

Hey

Hey or Hey! may refer to:

Interjection

Music

Albums

Songs

Hey! (Jullie album)

Hey! is the debut studio album by Brazilian recording artist Jullie. It was released on September 22, 2009 by Deckdisc. After writing songs for several established acts, Jullie released this album. The main theme of the songs is girl power. The songs are mostly inspired by Jullie's love of youth, rebellion, and discover who you are in 4.modern lifestyle. Musically, the album drew inspiration from pop and pop rock influenced by singers like Lily Allen, Madonna, Alanis Morissette, and its main reference, Katy Perry, directed to a feminist position. The album was praised by the young, calling Jullie as "Brazilian Katy Perry" for his music style and way of dressing. The first single "Alice" was released in April and the second single "Hey!" was released in November, 2009.

Track listing

References

External links

Hey (interjection)

Hey is an interjection usually used in the English language as a summonsing or attention-getting device. It is usually marked with an exclamation point. It is also one example of an interjection that speakers may use to express surprise. Some, such as the American grammarian Goold Brown, have suggested that the interjection "Hey" could be a corruption of the adjective "Sigh".

References