Mathematical proofA mathematical proof is a deductive argument for a mathematical statement, showing that the stated assumptions logically guarantee the conclusion. The argument may use other previously established statements, such as theorems; but every proof can, in principle, be constructed using only certain basic or original assumptions known as axioms, along with the accepted rules of inference. Proofs are examples of exhaustive deductive reasoning which establish logical certainty, to be distinguished from empirical arguments or non-exhaustive inductive reasoning which establish "reasonable expectation".
Arc lengthArc length is the distance between two points along a section of a curve. Determining the length of an irregular arc segment by approximating the arc segment as connected (straight) line segments is also called curve rectification. A rectifiable curve has a finite number of segments in its rectification (so the curve has a finite length). If a curve can be parameterized as an injective and continuously differentiable function (i.e., the derivative is a continuous function) , then the curve is rectifiable (i.
Standard diving dressStandard diving dress, also known as hard-hat or copper hat equipment, deep sea diving suit or heavy gear, is a type of diving suit that was formerly used for all relatively deep underwater work that required more than breath-hold duration, which included marine salvage, civil engineering, pearl shell diving and other commercial diving work, and similar naval diving applications. Standard diving dress has largely been superseded by lighter and more comfortable equipment.
Immune thrombocytopenic purpuraImmune thrombocytopenic purpura (ITP), also known as idiopathic thrombocytopenic purpura or immune thrombocytopenia, is a type of thrombocytopenic purpura characterized by a low platelet count in the absence of other causes, and accompanied by a red-purple rash called purpura. It leads to an increased risk of bleeding. ITP manifests in two distinct clinical syndromes: an acute form observed in children, and chronic conditions observed in adults.
Unit of lengthA unit of length refers to any arbitrarily chosen and accepted reference standard for measurement of length. The most common units in modern use are the metric units, used in every country globally. In the United States the U.S. customary units are also in use. British Imperial units are still used for some purposes in the United Kingdom and some other countries. The metric system is sub-divided into SI and non-SI units.
HatA hat is a head covering which is worn for various reasons, including protection against weather conditions, ceremonial reasons such as university graduation, religious reasons, safety, or as a fashion accessory. Hats which incorporate mechanical features, such as visors, spikes, flaps, braces or beer holders shade into the broader category of headgear. In the past, hats were an indicator of social status. In the military, hats may denote nationality, branch of service, rank or regiment.
Conic sectionA conic section, conic or a quadratic curve is a curve obtained from a cone's surface intersecting a plane. The three types of conic section are the hyperbola, the parabola, and the ellipse; the circle is a special case of the ellipse, though it was sometimes called as a fourth type. The ancient Greek mathematicians studied conic sections, culminating around 200 BC with Apollonius of Perga's systematic work on their properties. The conic sections in the Euclidean plane have various distinguishing properties, many of which can be used as alternative definitions.
Top hatA top hat (also called a high hat, a cylinder hat, or, informally, a topper) is a tall, flat-crowned hat traditionally associated with formal wear in Western dress codes, meaning white tie, morning dress, or frock coat. Traditionally made of black silk or sometimes grey, the top hat emerged in Western fashion by the end of the 18th century. Although it declined by the time of the counterculture of the 1960s, it remains a formal fashion accessory. A collapsible variant of a top hat, developed in the 19th century, is known as an opera hat.
De factoDe facto (deɪ_ˈfæktoʊ,_di-,_də- ; de facto deː ˈfaktoː, in fact) describes practices that exist in reality, regardless of whether they are officially recognized by laws or other formal norms. It is commonly used to refer to what happens in practice, in contrast with de jure ("by law"), which refers to things that happen according to official law, regardless of whether the practice exists in reality. In jurisprudence, it mainly means "practiced, but not necessarily defined by law" or "practiced or is valid, but not officially established".
Free softwareFree software or libre software or libreware is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, not price; all users are legally free to do what they want with their copies of a free software (including profiting from them) regardless of how much is paid to obtain the program.
De jureIn law and government, de jure (deɪ_ˈdʒʊəri,di-,_ˈjʊər- ; Latin: dē iūre deː ˈjuːrɛ, by law) describes practices that are legally recognized, regardless of whether the practice exists in reality. In contrast, ("in fact") describes situations that exist in reality, even if not legally recognized. Between 1805 and 1914, the ruling dynasty of Egypt were subject to the rulers of the Ottoman Empire, but acted as de facto independent rulers who maintained a polite fiction of Ottoman suzerainty.
Free contentFree content, libre content, libre information, or free information, is any kind of functional work, work of art, or other creative content that meets the definition of a free cultural work, meaning "works or expressions which can be freely studied, applied, copied and/or modified, by anyone, for any purpose." A free cultural work is, according to the definition of Free Cultural Works, one that has no significant legal restriction on people's freedom to: use the content and benefit from using it, study the content and apply what is learned, make and distribute copies of the content, change and improve the content and distribute these derivative works.
