What is "f4"

init. A rating of 4 on the Fujita scale

In mathematics, F is the name of a Lie group and also its Lie algebra f. It is one of the five exceptional simple Lie groups. F has rank 4 and dimension 52. The compact form is simply connected and its outer automorphism group is the trivial group. Its fundamental representation is 26-dimensional.

The compact real form of F is the isometry group of a 16-dimensional Riemannian manifold known as the octonionic projective plane OP. This can be seen systematically using a construction known as the magic square, due to Hans Freudenthal and Jacques Tits.

There are 3 real forms: a compact one, a split one, and a third one. They are the isometry groups of the three real Albert algebras.

The F Lie algebra may be constructed by adding 16 generators transforming as a spinor to the 36-dimensional Lie algebra so(9), in analogy with the construction of E.

In older books and papers, F is sometimes denoted by E.

F4 or JVKV is a Taiwanese boy band consisting of Jerry Yan, Vanness Wu, Ken Chu, and Vic Chou. The group was formed in 2001 after the Taiwanese drama Meteor Garden that they starred in was widely successful. Together they have starred in several Taiwanese drama series and released three albums, Meteor Rain (2001), Fantasy 4ever (2002), and Waiting for You (2007).

In 2007, due to copyright issues, the group changed its name to JVKV, using the initials of its members. Other than their home country, Taiwan, they have also attained popularity in other parts of Asia, such as China, Hong Kong, Singapore, Malaysia, Thailand, Indonesia, Japan, South Korea and The Philippines.

F4, F.IV, F04, F 4, F.4 or F-4 may refer to:

F4 is a paper format of size . Although metric, based on the A4 paper size, and named to suggest that it is part of the official ISO 216 paper sizes, it appears to be only a de facto standard.

It may be referred to as "foolscap" or "folio" because of its similarity to the traditional Foolscap folio size of .

F4, formerly known as F4-Toys, is a French video game developer based in Paris. The company is located near the Champs Élysées. Currently is in development new STD inside their office. Release is expected to be set on 31st February 2017.

F4, also T4 and SP4, is a wheelchair sport classification that corresponds to the neurological level T1- T7. Historically, it was known as 1C Incomplete, 2 Complete, or Upper 3 Complete. People in this class have normal upper limb function, and functional issues with muscles below the nipple line.

There are comparable F4 classes in a number of sports. For athletics, these are T54 and F54. In cycling, these are H4 or H5. Swimming classes include S3, SB3, S4 and S5. The process for classification into this class has a medical and functional classification process. This process is often sport specific.