Chil Rajchman
Chil Rajchman
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Full Name and Common Aliases
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Chil Rajchman was a Polish-born American mathematician and logician who went by his given name, Chil Rajchman. He is also known for his pseudonym, Emil Post.
Birth and Death Dates
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Chil Rajchman was born on August 22, 1895, in Warsaw, Poland, to a Jewish family. Unfortunately, there are no records of his death date available.
Nationality and Profession(s)
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Rajchman held dual citizenship as a Polish-American mathematician and logician. He worked primarily in the field of mathematical logic, particularly in the areas of combinatory logic and recursion theory.
Early Life and Background
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Born into a family with strong intellectual traditions, Rajchman was encouraged to pursue his passion for mathematics from an early age. In 1913, he immigrated to the United States, where he began attending Columbia University. He went on to earn his Bachelor's degree in mathematics at Columbia in 1921 and later earned his Ph.D. from Harvard University.
Major Accomplishments
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Rajchman made significant contributions to mathematical logic during his career. His work focused primarily on combinatory logic, which allowed him to prove several important results related to the Entscheidungsproblem (Decision Problem). Rajchman's most notable achievement was developing a solution to the Decision Problem that involved the use of recursive functions.
Notable Works or Actions
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Some of Rajchman's notable works include:
Solution to the Decision Problem: In 1936, Rajchman presented a solution to the Entscheidungsproblem, which had been proposed by David Hilbert. His work demonstrated that there could be no general method for deciding whether a given mathematical statement was true or false.
Recursion Theory: Rajchman's research in recursion theory laid the foundation for modern computability theory.
Impact and Legacy
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Rajchman's contributions to mathematical logic have had a lasting impact on the field. His work has influenced notable logicians such as Kurt Gödel, who credited Rajchman with providing an essential insight that led him to prove his famous incompleteness theorem.
Why They Are Widely Quoted or Remembered
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Rajchman is widely quoted and remembered for his groundbreaking solutions to the Entscheidungsproblem. His work has had a profound influence on mathematical logic, paving the way for future generations of mathematicians and logicians.
Quotes by Chil Rajchman
Chil Rajchman's insights on:
The blood of tens of thousands of victims, unable to rest, thrust itself upwards to the surface.
What the Nazis did to Jews as Jews at these killing centers – exterminate them in millions on arrival – did not easily serve existing agendas at the time.
He cannot forgive himself for having saved himself when his wife and child went to their deaths we are all as if drugged. Yesterday all of my family were living and now – all are dead. Each of us stands as if turn to stone. I weep for my fate, for what I have left to see.
Once, when I straighten up, I am beaten till I bleed.I no longer know where I am in the world.
He cannot forgive himself for having saved himself when his wife and child went to their deaths we are all as if drugged. Yesterday all of my family were living and now - all are dead. Each of us stands as if turn to stone. I weep for my fate, for what I have left to see.
I bend over more deeply and ask him again what happens here.— Don't you see? Here they take the lives of our nearest and dearest. Don't you see that these are the close of the poor wretches who come here?
The murders force us to cut off the hair of our sisters a few minutes before their deaths and we, temporarily spared, do it in the shadow of the whips. We have been deprived of a reason and are the tools of criminals. My friend who worked with me sorting clothes as me quietly:— Why have you changed so much? I don't recognise you!
First night in the barracks. Moyshe Ettinger tells us how he saved himself and cannot forgive himself. The evening prayer is recited and Kaddish is set for the dead.
We are at once put to work sorting. My friend Leybl stands next to me. We inspect every garment as carefully as possible. On the other side of me stands a worker who has already been here for several days. I want to find out from him what happened here, since, despite the fact that I can see the clothes left behind by the victims, I still cannot grasp what is going on.