If This Is a Man to shape the book, giving it a clear sense of direction. In January 1947, the manuscript was rejected by Einaudi. The writers Cesare Pavese and Natalia Ginzburg thought it too early after the war for such an account. Levi managed to find a smaller publisher, De Silva, who printed 2,500 copies of the book, 1,500 of which were sold, mostly in Levi's hometown of Turin. In 1955, Levi signed a contract with Einaudi for a new edition, which was published in 1958. The initial printing of 2000 copies was followed by a second of the same size. An English translation
Distance from a point to a plane the closest point to the origin may be expressed more succinctly using notation from linear algebra. The expression formula_19 in the definition of a plane is a dot product formula_20, and the expression formula_21 appearing in the solution is the squared norm formula_22. Thus, if formula_23 is a given vector, the plane may be described as the set of vectors formula_24 for which formula_25 and the closest point on this plane is the vector Written in Cartesian form, the closest point is given by formula_27 for formula_28 where and the distance from formula_30 to the hyperplane is Thus in formula_32