Natural user interfaceIn computing, a natural user interface (NUI) or natural interface is a user interface that is effectively invisible, and remains invisible as the user continuously learns increasingly complex interactions. The word "natural" is used because most computer interfaces use artificial control devices whose operation has to be learned. Examples include voice assistants, such as Alexa and Siri, touch and multitouch interactions on today's mobile phones and tablets, but also touch interfaces invisibly integrated into the textiles furnitures.
Complex numberIn mathematics, a complex number is an element of a number system that extends the real numbers with a specific element denoted i, called the imaginary unit and satisfying the equation ; every complex number can be expressed in the form , where a and b are real numbers. Because no real number satisfies the above equation, i was called an imaginary number by René Descartes. For the complex number , a is called the , and b is called the . The set of complex numbers is denoted by either of the symbols or C.
Fair useFair use is a doctrine in United States law that permits limited use of copyrighted material without having to first acquire permission from the copyright holder. Fair use is one of the limitations to copyright intended to balance the interests of copyright holders with the public interest in the wider distribution and use of creative works by allowing as a defense to copyright infringement claims certain limited uses that might otherwise be considered infringement.
Cosquer CaveThe Cosquer Cave is located in the Calanque de Morgiou in Marseille, France, near Cap Morgiou. The entrance to the cave is located underwater, due to the Holocene sea level rise. The cave contains various prehistoric rock art engravings. Its submarine entrance was discovered in 1985 by Henri Cosquer, a professional diver. The underwater passage leading to the cave was progressively explored until 1990 by cave divers without the divers being aware of the archaeological character of the cave.
Cave paintingIn archaeology, cave paintings are a type of parietal art (which category also includes petroglyphs, or engravings), found on the wall or ceilings of caves. The term usually implies prehistoric origin, and the oldest known are more than 40,000 years old (art of the Upper Paleolithic) and found in the caves in the district of Maros (Sulawesi, Indonesia). The oldest are often constructed from hand stencils and simple geometric shapes. More recently, in 2021, cave art of a pig found in Sulawesi, Indonesia, and dated to over 45,500 years ago, has been reported.
Alexandroff extensionIn the mathematical field of topology, the Alexandroff extension is a way to extend a noncompact topological space by adjoining a single point in such a way that the resulting space is compact. It is named after the Russian mathematician Pavel Alexandroff. More precisely, let X be a topological space. Then the Alexandroff extension of X is a certain compact space X* together with an open embedding c : X → X* such that the complement of X in X* consists of a single point, typically denoted ∞.
