Problem: Solar energy:

Solar cookers use sunlight for cooking, drying and pasteurization. They can be grouped into three broad categories: box cookers, panel cookers and reflector cookers. The simplest solar cooker is the box cooker first built by Horace de Saussure in 1767. A basic box cooker consists of an insulated container with a transparent lid. It can be used effectively with partially overcast skies and will typically reach temperatures of 90150 C (194302 F). Panel cookers use a reflective panel to direct sunlight onto an insulated container and reach temperatures comparable to box cookers. Reflector cookers use various concentrating geometries (dish, trough, Fresnel mirrors) to focus light on a cooking container. These cookers reach temperatures of 315 C (599 F) and above but require direct light to function properly and must be repositioned to track the Sun.

Who created the box cooker?
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A: Horace de Saussure

Problem: In many situations it is desirable to consider two group elements the same if they differ by an element of a given subgroup. For example, in D4 above, once a reflection is performed, the square never gets back to the r2 configuration by just applying the rotation operations (and no further reflections), i.e. the rotation operations are irrelevant to the question whether a reflection has been performed. Cosets are used to formalize this insight: a subgroup H defines left and right cosets, which can be thought of as translations of H by arbitrary group elements g. In symbolic terms, the left and right cosets of H containing g are
What question are cosets irrelevant to?
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Answer: unanswerable

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Law enforcement in Ancient China was carried out by "prefects" for thousands of years since it developed in both the Chu and Jin kingdoms of the Spring and Autumn period. In Jin, dozens of prefects were spread across the state, each having limited authority and employment period. They were appointed by local magistrates, who reported to higher authorities such as governors, who in turn were appointed by the emperor, and they oversaw the civil administration of their "prefecture", or jurisdiction. Under each prefect were "subprefects" who helped collectively with law enforcement in the area. Some prefects were responsible for handling investigations, much like modern police detectives. Prefects could also be women. The concept of the "prefecture system" spread to other cultures such as Korea and Japan.
What period was the Chin kingdom in?
A: unanswerable

Context and question: During the 1950s and 1960s, FBI officials became increasingly concerned about the influence of civil rights leaders, whom they believed had communist ties or were unduly influenced by them. In 1956, for example, Hoover sent an open letter denouncing Dr. T.R.M. Howard, a civil rights leader, surgeon, and wealthy entrepreneur in Mississippi who had criticized FBI inaction in solving recent murders of George W. Lee, Emmett Till, and other blacks in the South. The FBI carried out controversial domestic surveillance in an operation it called the COINTELPRO, which was short for "COunter-INTELligence PROgram." It was to investigate and disrupt the activities of dissident political organizations within the United States, including both militant and non-violent organizations. Among its targets was the Southern Christian Leadership Conference, a leading civil rights organization with clergy leadership.
What agency had Dr. T.R.M. Howard criticized?
Answer: FBI

Question: In the 1990s two icons by the Russian icon painter Sergei Fyodorov were hung in the abbey. On 6 September 1997 the funeral of Diana, Princess of Wales, was held at the Abbey. On 17 September 2010 Pope Benedict XVI became the first pope to set foot in the abbey.
Is there an answer to this question: On what date did the first pope set foot in the abbey?

Answer: 17 September 2010

Problem: Alaska:

Cities not served by road, sea, or river can be reached only by air, foot, dogsled, or snowmachine, accounting for Alaska's extremely well developed bush air servicesan Alaskan novelty. Anchorage and, to a lesser extent Fairbanks, is served by many major airlines. Because of limited highway access, air travel remains the most efficient form of transportation in and out of the state. Anchorage recently completed extensive remodeling and construction at Ted Stevens Anchorage International Airport to help accommodate the upsurge in tourism (in 2012-2013, Alaska received almost 2 million visitors).

Which two cities are unserved by major airlines?
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A:
unanswerable