In mathematics, the four color theorem, or the four color map theorem, states that, given any separation of a plane into contiguous regions, producing a figure called a map, no more than four colors are required to color the regions of the map so that no two adjacent regions have the same color. Adjacent means that two regions share a common boundary curve segment, not merely a corner where three or more regions meet. It was the first major theorem to be proved using a computer. Initially, this proof was not accepted by all mathematicians because the computer-assisted proof was infeasible for a human to check by hand. Since then the proof has gained wide acceptance, although some doubters remain.
A regular expression, regex or regexp is a sequence of characters that define a search pattern. Usually this pattern is used by string searching algorithms for "find" or "find and replace" operations on strings, or for input validation. It is a technique that developed in theoretical computer science and formal language theory.
A pattern is a regularity in the world, man-made design, or abstract ideas. As such, the elements of a pattern repeat in a predictable manner. A geometric pattern is a kind of pattern formed of geometric shapes and typically repeated like a wallpaper design.
In software engineering, a software design pattern is a general, reusable solution to a commonly occurring problem within a given context in software design. It is not a finished design that can be transformed directly into source or machine code. It is a description or template for how to solve a problem that can be used in many different situations. Design patterns are formalized best practices that the programmer can use to solve common problems when designing an application or system.
Isotropic etching is a method commonly used in semiconductors to remove material from a substrate via a chemical process using an etchant substance. The etchant may be in liquid-, gas- or plasma-phase, although liquid etchants such as buffered hydrofluoric acid (BHF) for silicon dioxide etching are more often used. Unlike anisotropic etching, isotropic etching does not etch in a single direction, but rather etches in multiple directions within the substrate. Any horizontal component of the etch direction may therefore result in undercutting of patterned areas, and significant changes to device characteristics. Isotropic etching may occur unavoidably, or it may be desirable for process reasons.
A power outage is a short-term or a long-term loss of the electric power to a particular area.
A Bayer filter mosaic is a color filter array (CFA) for arranging RGB color filters on a square grid of photosensors. Its particular arrangement of color filters is used in most single-chip digital image sensors used in digital cameras, camcorders, and scanners to create a color image. The filter pattern is 50% green, 25% red and 25% blue, hence is also called BGGR, RGBG, GRGB, or RGGB.
Photosensitive epilepsy (PSE) is a form of epilepsy in which seizures are triggered by visual stimuli that form patterns in time or space, such as flashing lights; bold, regular patterns; or regular moving patterns.
Paul Wilhelm "Willy" Kyrklund was a Finnish Swedish-speaking author who lived in Uppsala, Sweden.
An open-label trial, or open trial, is a type of clinical trial in which both the researchers and participants know which treatment is being administered.
This contrasts with single blind and double blind experimental designs, where participants are not aware of what treatment they are receiving.
A glossy display is an electronic display with a glossy surface. In certain light environments glossy displays provide better color intensity and contrast ratios than matte displays. The primary disadvantage of these displays is their tendency to reflect any external light, often resulting in an undesirable glare.
In cryptography, a pre-shared key (PSK) is a shared secret which was previously shared between the two parties using some secure channel before it needs to be used.
A tabby is any domestic cat that has a coat featuring distinctive stripes, dots, lines or swirling patterns, always together with a mark resembling an 'M' on its forehead. Tabbies are sometimes erroneously assumed to be a cat breed. In fact, the tabby pattern is found in many breeds, and is a genetic landrace common among the general mixed-breed population. The tabby pattern is a naturally occurring feature that may be related to the coloration of the domestic cat's direct ancestor, the African wildcat, which—along with the European wildcat and Asiatic wildcat —has a similar coloration. A genetic study found five genetic clusters from tabbies to be ancestral to wildcats of various parts of the world.
Ecological Building is both a design process and the structure that is a result of such a design process.
Combinatorics on words is a fairly new field of mathematics, branching from combinatorics, which focuses on the study of words and formal languages. The subject looks at letters or symbols, and the sequences they form. Combinatorics on words affects various areas of mathematical study, including algebra and computer science. There have been a wide range of contributions to the field. Some of the first work was on square-free words by Thue in the early 1900s. He and colleagues observed patterns within words and tried to explain them. As time went on, combinatorics on words became useful in the study of algorithms and coding. It led to developments in abstract algebra and answering open questions.
Yadua the Babylonian was a 2nd-century tanna of the fifth generation. He was born in Babylonia but subsequently moved to Syria Palæstina, becoming the pupil of Rabbi Meir, a prominent rabbi and student of the Acher, one of the leading tannaim who became a heretic.
In mathematics, a sesquipower or Zimin word is a string over an alphabet with identical prefix and suffix. Sesquipowers are unavoidable patterns, in the sense that all sufficiently long strings contain one.
V Chennai Warriors is a tennis team representing the Indian city of Chennai in the Champions Tennis League. The team was initially supposed to take part in the 2014 Champions Tennis League but due to unavoidable circumstances they backed out at the last moment and eventually the Hyderabad Aces went on to replace them in the 2014 edition. On 14 November 2015, the V Chennai Warriors franchise was unveiled by Vijay Amritraj, founder of the Champions Tennis League. The team is owned by Prabhu Deva, a renowned actor and Ishari K Ganesh, founder Chairman and Chancellor of the Vels University in Chennai. The players who represented this team in the 2015 season were Rainer Schuettler, Fernando Verdasco, Heather Watson and Vishnu Vardhan. The 2015 tournament began on 23 November and ended on 6 December with the V Chennai Warriors finishing last in Group B with one win and three losses from four games. Group B also had the likes of Hyderabad Aces and Nagpur Orangers.
Steven Levenson is an American playwright and television writer. He won the 2017 Tony Award for Best Book of a Musical for Dear Evan Hansen.
