Question: What nationality was the man who derived the Einstein–Rosen metric with Albert Einstein?

Context articles: Kähler–Einstein metric
Albert Einstein Peace Prize
Nathan Rosen
Helen Dukas
Einstein–Rosen metric
Einstein Gargoyle
Einstein–de Sitter universe
Ilse Rosenthal-Schneider
Einstein manifold
Albert Einstein Award

In differential geometry, a Kähler–Einstein metric on a complex manifold is a Riemannian metric that is both a Kähler metric and an Einstein metric.
 A manifold is said to be Kähler–Einstein if it admits a Kähler–Einstein metric.
 The most important special case of these are the Calabi–Yau manifolds, which are Kähler and Ricci-flat.
The Albert Einstein Peace Prize is/was a peace prize awarded annually since 1980 by the Albert Einstein Peace Prize Foundation.
 The Foundation dates from 1979, the centenary of the birth of Albert Einstein, and evokes the Russell–Einstein Manifesto which urges nuclear disarmament.
 It was established, with the sponsorship of the trustees of Einstein's estate, by William M. Swartz (1912–87) a wealthy businessman and the grandfather of activist Aaron Swartz.
 William M. Swartz was involved in the Pugwash Conferences on Science and World Affairs and established the Foundation in part to support Pugwash.
 Prize winners, mainly active in nuclear disarmament, receive(d) $50,000.
Nathan Rosen (Hebrew: נתן רוזן; March 22, 1909 – December 18, 1995) was an American-Israeli physicist noted for his study on the structure of the hydrogen atom and his work with Albert Einstein and Boris Podolsky on entangled wave functions and the EPR paradox.
 The Einstein–Rosen bridge, later named the wormhole, was a theory of Nathan Rosen.
Helen Dukas (17 October 1896 – 10 February 1982) was Albert Einstein's secretary.
 She also co-authored "" and co-edited "Albert Einstein: The Human Side" with Dr. Banesh Hoffmann.
 Dukas was one of two trustees chosen by Einstein, according to his Last Will and Testament, to hold the literary rights to all of his manuscripts, copyrights, publication rights, royalties, and royalty agreements.
 The other trustee was the economist Dr. Otto Nathan.
 In short, Dukas and Dr. Nathan were the "executors of his literary heritage."
 They collaborated on the compilation of "The Collected Papers of Albert Einstein," using documents that were subsequently donated to the Hebrew University of Jerusalem.
The Einstein–Rosen metric is an exact solution of Einstein's field equation.
 It was derived by Albert Einstein and Nathan Rosen in 1937.
 It is the first exact solution of Einstein's equation that described the propagation of a gravitational wave.
Einstein Gargoyle, also referred to as Albert Einstein, Einstein, and Einstein Gargoyles, is an outdoor 1986 sculpture by Wayne Chabre, installed on the exterior of Willamette Hall on the University of Oregon campus in Eugene, Oregon, United States.
 The portrait bust depicts Albert Einstein in high relief with a fluttering necktie, and was inspired by a photograph of the scientist on his birthday.
 It is made of hammered copper sheet and measures approximately 2.5 ft x 1.5 ft x 1.5 ft .
 The sculpture's condition was undetermined when it was surveyed by the Smithsonian Institution's "Save Outdoor Sculpture!
" program in March 1993.
 The sculpture is administered by the University of Oregon.
The Einstein–de Sitter universe is a model of the universe proposed by Albert Einstein and Willem de Sitter in 1932.
 On first learning of Edwin Hubble's discovery of a linear relation between the redshift of the galaxies and their distance, Einstein set the cosmological constant to zero in the Friedmann equations, resulting in a model of the expanding universe known as The Friedmann-Einstein universe.
 In 1932, Einstein and de Sitter proposed an even simpler cosmic model by assuming a vanishing spatial curvature as well as a vanishing cosmological constant.
 In modern parlance, the Einstein–de Sitter universe can be described as a cosmological model for a flat matter-only Friedmann–Lemaître–Robertson–Walker metric (FLRW) universe.
Ilse Rosenthal-Schneider (April 25, 1891 – February 6, 1990) was a German-Australian physicist and philosopher.
 She is best known for her collaboration and correspondence with physicists Albert Einstein, Max von Laue, and Max Planck.
 Rosenthal-Schneider earned a PhD in philosophy in 1920 at the University of Berlin, where she first met Albert Einstein.
 After leaving Nazi Germany and emigrating to Australia in 1938, she became a tutor in the German department at the University of Sydney in 1945 and taught history and philosophy of science.
 In the 1940s and 1950s, she exchanged a series of letters with Albert Einstein about philosophical aspects of physics, such as theory of relativity, fundamental constants and physical reality.
 She remained in contact with Einstein through correspondence until the death of Einstein in 1955.
In differential geometry and mathematical physics, an Einstein manifold is a Riemannian or pseudo-Riemannian differentiable manifold whose Ricci tensor is proportional to the metric.
 They are named after Albert Einstein because this condition is equivalent to saying that the metric is a solution of the vacuum Einstein field equations (with cosmological constant), although both the dimension and the signature of the metric can be arbitrary, thus not being restricted to the four-dimensional Lorentzian manifolds usually studied in general relativity.
This award should not be confused with many others named after the famous physicist, such as the Albert Einstein World Award of Science given by the World Cultural Council (since 1984), the Albert Einstein Medal given by the Albert Einstein Society (since 1979), nor with the Hans Albert Einstein Award, named after his son and given by the American Society of Civil Engineers (since 1988).
 It was established much earlier than these, when Einstein was still alive and was a professor at the Institute for Advanced Study.
 It has been called "the highest of its kind in the United States" by "The New York Times".
 Some considered it as "the prestigious equivalent of a Nobel Prize".