Problem: Several prominent American literary figures lived in New York during the 1830s and 1840s, including William Cullen Bryant, Washington Irving, Herman Melville, Rufus Wilmot Griswold, John Keese, Nathaniel Parker Willis, and Edgar Allan Poe. Public-minded members of the contemporaneous business elite lobbied for the establishment of Central Park, which in 1857 became the first landscaped park in an American city.
In what year was Central Park founded?
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Answer: 1857

Problem: The national postal infrastructure was completely destroyed during the civil war. In order to fill the vacuum, Somali Post signed an agreement in 2003 with the United Arab Emirates' Emirates Post to process mail to and from Somalia. Emirates Post's mail transit hub at the Dubai International Airport was then used to forward mail from Somalia to the UAE and various Western destinations, including Italy, the Netherlands, the United Kingdom, Sweden, Switzerland and Canada.
What country did the Somali Post parner with before the civil war?
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Answer: unanswerable

Problem: In general relativity, a vanishing stress-energy tensor implies, through Einstein field equations, the vanishing of all the components of the Ricci tensor. Vacuum does not mean that the curvature of space-time is necessarily flat: the gravitational field can still produce curvature in a vacuum in the form of tidal forces and gravitational waves (technically, these phenomena are the components of the Weyl tensor). The black hole (with zero electric charge) is an elegant example of a region completely "filled" with vacuum, but still showing a strong curvature.
Who's equations helped to imply vanishing of the Ricci tensor?
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Answer:
Einstein