Have a deep view into what people are curious about.

🔗 Mathematics

The moving sofa problem or sofa problem is a two-dimensional idealisation of real-life furniture-moving problems and asks for the rigid two-dimensional shape of largest area A that can be maneuvered through an L-shaped planar region with legs of unit width. The area A thus obtained is referred to as the sofa constant. The exact value of the sofa constant is an open problem.

🔗 Computing

The IBM 5100 Portable Computer is a portable computer (one of the first) introduced in September 1975, six years before the IBM Personal Computer. It was the evolution of a prototype called the SCAMP (Special Computer APL Machine Portable) that was developed at the IBM Palo Alto Scientific Center in 1973. In January 1978, IBM announced the IBM 5110, its larger cousin, and in February 1980 IBM announced the IBM 5120. The 5100 was withdrawn in March 1982.

When the IBM PC was introduced in 1981, it was originally designated as the IBM 5150, putting it in the "5100" series, though its architecture was unrelated to the IBM 5100's.

🔗 Human rights 🔗 Philosophy 🔗 Freedom of speech 🔗 Philosophy/Logic 🔗 Politics 🔗 Psychology 🔗 Sociology 🔗 Education 🔗 Popular Culture 🔗 Debating

A lie-to-children is a simplified, and often technically incorrect, explanation of technical or complex subjects employed as a teaching method. Educators who employ lies-to-children do not intend to deceive, but instead seek to 'meet the child/pupil/student where they are', in order to facilitate initial comprehension, which they build upon over time as the learner's intellectual capacity expands. The technique has been incorporated by academics within the fields of biology, evolution, bioinformatics and the social sciences.

🔗 Physics

The Elitzur–Vaidman bomb-tester is a quantum mechanics thought experiment that uses interaction-free measurements to verify that a bomb is functional without having to detonate it. It was conceived in 1993 by Avshalom Elitzur and Lev Vaidman. Since their publication, real-world experiments have confirmed that their theoretical method works as predicted.

The bomb tester takes advantage of two characteristics of elementary particles, such as photons or electrons: nonlocality and wave-particle duality. By placing the particle in a quantum superposition, it is possible for the experiment to verify that the bomb works without triggering its detonation, although there is still a 50% chance that the bomb will detonate in the effort.

🔗 Internet culture 🔗 Lists 🔗 Languages

This is a list of slang used by Generation Z (Gen Z), generally those born between the late 1990s and the late 2000s in the Western world.

🔗 United States 🔗 Terrorism 🔗 Socialism 🔗 Michigan 🔗 Chicago

The Weather Underground Organization (WUO), commonly known as the Weather Underground, was a radical left militant organization active in the late 1960s and 1970s, founded on the Ann Arbor campus of the University of Michigan. It was originally called the Weathermen. The WUO organized in 1969 as a faction of Students for a Democratic Society (SDS) largely composed of the national office leadership of SDS and their supporters. Beginning in 1974, the organization's express political goal was to create a revolutionary party to overthrow American imperialism.

The FBI described the WUO as a domestic terrorist group, with revolutionary positions characterized by black power and opposition to the Vietnam War. The WUO took part in domestic attacks such as the jailbreak of Timothy Leary in 1970. The "Days of Rage" was the WUO's first riot in October 1969 in Chicago, timed to coincide with the trial of the Chicago Seven. In 1970, the group issued a "Declaration of a State of War" against the United States government under the name "Weather Underground Organization".

In the 1970s, the WUO conducted a bombing campaign targeting government buildings and several banks. Some attacks were preceded by evacuation warnings, along with threats identifying the particular matter that the attack was intended to protest. Three members of the group were killed in an accidental Greenwich Village townhouse explosion, but none were killed in any of the bombings. The WUO communiqué issued in connection with the bombing of the United States Capitol on March 1, 1971 indicated that it was "in protest of the U.S. invasion of Laos". The WUO asserted that its May 19, 1972 bombing of the Pentagon was "in retaliation for the U.S. bombing raid in Hanoi". The WUO announced that its January 29, 1975 bombing of the United States Department of State building was "in response to the escalation in Vietnam".

The WUO began to disintegrate after the United States reached a peace accord in Vietnam in 1973, and it was defunct by 1977.

The group took its name from Bob Dylan's lyric, "You don't need a weatherman to know which way the wind blows", from the song "Subterranean Homesick Blues" (1965). That Dylan line was also the title of a position paper distributed at an SDS convention in Chicago on June 18, 1969. This founding document called for a "White fighting force" to be allied with the "Black Liberation Movement" and other radical movements to achieve "the destruction of U.S. imperialism and form a classless communist world".

🔗 Medicine 🔗 Medicine/Neurology

Type 3 diabetes is a proposed term to describe the interlinked association between type 1 and type 2 diabetes, and Alzheimer's disease. This term is used to look into potential triggers of Alzheimer's disease in people with diabetes.

The proposed progression from diabetes to Alzheimer's disease is inadequately understood; however there are a number of hypotheses describing potential links between the two diseases. The internal mechanism of Insulin resistance and other metabolic risk factors such as hyperglycaemia, caused by oxidative stress and lipid peroxidation are common processes thought to be contributors to the development of Alzheimer's disease in diabetics.

Diagnosis for this disease is different between patients with type 1 and type 2 diabetes. Type 1 diabetes is usually discovered in children and adolescence while type 2 diabetic patients are often diagnosed later in life. While Type 3 diabetes is not a diagnosis in itself, a diagnosis of suspected Alzheimer's disease can be established through observational signs and sometimes with neuroimaging techniques such as Magnetic Resonance Imaging (MRI) to observe abnormalities in diabetic patient's brain tissue.

The techniques used to prevent the disease in patients with diabetes are similar to individuals who do not show signs of the disease. The four pillars of Alzheimer's disease prevention is currently used as a guide for individuals of whom are at risk of developing Alzheimer's disease.

Research into the effectiveness of Glucagon-like Peptide 1 and Melatonin administration to manage the progression of Alzheimer's disease in diabetic patients is currently being conducted to decrease the rate at which Alzheimer's disease progresses.

Labelling Alzheimer's disease as Type 3 Diabetes is generally controversial, and this definition is not a known medical diagnosis. While insulin resistance is a risk factor for the development of Alzheimer's disease and some other dementias, causes of Alzheimer's disease are likely to be much more complex than being explained by insulin factors on their own, and indeed several patients with Alzheimer's disease have normal insulin metabolism.

🔗 Biography 🔗 Internet culture 🔗 Mathematics 🔗 Biography/science and academia

Cleo was the pseudonym of an anonymous mathematician active on the mathematics Stack Exchange from 2013 to 2015, who became known for providing precise answers to complex mathematical integration problems without showing any intermediate steps. Due to the extraordinary accuracy and speed of the provided solutions, mathematicians debated whether Cleo was an individual genius, a collective pseudonym, or even an early artificial intelligence system.

During the poster's active period, Cleo posted 39 answers to advanced mathematical questions, primarily focusing on complex integration problems that had stumped other users. Cleo's answers were characterized by being consistently correct while providing no explanation of methodology, often appearing within hours of the original posts. The account claimed to be limited in interaction due to an unspecified medical condition.

The mystery surrounding Cleo's identity and mathematical abilities generated significant interest in the mathematical community, with users attempting to analyze solution patterns and writing style for clues. Some compared Cleo to historical mathematical figures like Srinivasa Ramanujan, known for providing solutions without conventional proofs. In 2025, Cleo was revealed to be Vladimir Reshetnikov, a software developer originally from Uzbekistan.

🔗 Books

The Autumn of the Middle Ages, The Waning of the Middle Ages, or Autumntide of the Middle Ages (published in 1919 as Herfsttij der Middeleeuwen and translated into English in 1924, German in 1924, and French in 1932), is the best-known work by the Dutch historian Johan Huizinga.

In the book, Huizinga presents the idea that the exaggerated formality and romanticism of late medieval court society was a defense mechanism against the constantly increasing violence and brutality of general society. He saw the period as one of pessimism, cultural exhaustion, and nostalgia, rather than of rebirth and optimism.

His main conclusion is that the combination of required modernization of statehood governance, stuck in traditionalism, in combination with the exhausting inclusion of an ever-growing corpus of Catholic rites and popular beliefs in daily life, led to the implosion of late medieval society. This provided light to the rise of (religious) individualism, humanism and scientific progress: the renaissance.

The book was nominated for the 1939 Nobel Prize for Literature, but lost to the Finnish writer Frans Eemil Sillanpää.

Huizinga's work later came under some criticism, especially for relying too heavily on evidence from the rather exceptional case of the Burgundian court. Other criticisms include the writing of the book being "old-fashioned" and "too literary".

A new English translation of the book was published in 1996 because of perceived deficiencies in the original translation. The new translation, by Rodney Payton and Ulrich Mammitzsch, was based on the second edition of the Dutch publication in 1921 and compared with the German translation published in 1924.

To mark the centenary of Herfsttij, a new translation by Diane Webb appeared in 2020, published by Leiden University Press: Autumntide of the Middle Ages. According to Benjamin Kaplan, this translation "captures Huizinga's original voice better than either of the two previous English editions". This new English edition also includes for the first time 300 full-colour illustrations of all the works of art Huizinga mentions in his text.

In the 1970s, Radio Netherlands produced an audio series about the book, entitled "Autumn of the Middle Ages: A Six-part History in Words and Music from the Low Countries".

🔗 Mathematics 🔗 Economics 🔗 Statistics 🔗 Sociology 🔗 Globalization

In economics, the Gini coefficient ( JEE-nee), sometimes called the Gini index or Gini ratio, is a measure of statistical dispersion intended to represent the income or wealth distribution of a nation's residents, and is the most commonly used measurement of inequality. It was developed by the Italian statistician and sociologist Corrado Gini and published in his 1912 paper Variability and Mutability (Italian: Variabilità e mutabilità).

The Gini coefficient measures the inequality among values of a frequency distribution (for example, levels of income). A Gini coefficient of zero expresses perfect equality, where all values are the same (for example, where everyone has the same income). A Gini coefficient of one (or 100%) expresses maximal inequality among values (e.g., for a large number of people, where only one person has all the income or consumption, and all others have none, the Gini coefficient will be very nearly one). For larger groups, values close to one are very unlikely in practice. Given the normalization of both the cumulative population and the cumulative share of income used to calculate the Gini coefficient, the measure is not overly sensitive to the specifics of the income distribution, but rather only on how incomes vary relative to the other members of a population. The exception to this is in the redistribution of income resulting in a minimum income for all people. When the population is sorted, if their income distribution were to approximate a well-known function, then some representative values could be calculated.

The Gini coefficient was proposed by Gini as a measure of inequality of income or wealth. For OECD countries, in the late 20th century, considering the effect of taxes and transfer payments, the income Gini coefficient ranged between 0.24 and 0.49, with Slovenia being the lowest and Mexico the highest. African countries had the highest pre-tax Gini coefficients in 2008–2009, with South Africa the world's highest, variously estimated to be 0.63 to 0.7, although this figure drops to 0.52 after social assistance is taken into account, and drops again to 0.47 after taxation. The global income Gini coefficient in 2005 has been estimated to be between 0.61 and 0.68 by various sources.

There are some issues in interpreting a Gini coefficient. The same value may result from many different distribution curves. The demographic structure should be taken into account. Countries with an aging population, or with a baby boom, experience an increasing pre-tax Gini coefficient even if real income distribution for working adults remains constant. Scholars have devised over a dozen variants of the Gini coefficient.