Question: Who is the employer of the physicist who Mach number is named after?

Context paragraphs:
paragraph_text: In number theory, a branch of mathematics, a Hilbert number is a positive integer of the form (). The Hilbert numbers were named after David Hilbert.
title: Hilbert number
paragraph_text: On 14 October 1947, just under a month after the United States Air Force had been created as a separate service, the tests culminated in the first manned supersonic flight, piloted by Air Force Captain Charles ``Chuck ''Yeager in aircraft # 46 - 062, which he had christened Glamorous Glennis. The rocket - powered aircraft was launched from the bomb bay of a specially modified B - 29 and glided to a landing on a runway. XS - 1 flight number 50 is the first one where the X-1 recorded supersonic flight, at Mach 1.06 (361 m / s, 1,299 km / h, 807.2 mph) peak speed; however, Yeager and many other personnel believe Flight # 49 (also with Yeager piloting), which reached a top recorded speed of Mach 0.997 (339 m / s, 1,221 km / h), may have, in fact, exceeded Mach 1. (The measurements were not accurate to three significant figures and no sonic boom was recorded for that flight.)
title: Sound barrier
paragraph_text: The General Theory of Employment, Interest and Money was written by the English economist John Maynard Keynes. The book, generally considered to be his magnum opus, is largely credited with creating the terminology and shape of modern macroeconomics. Published in February 1936, it sought to bring about a revolution, commonly referred to as the ``Keynesian Revolution '', in the way some economists believe. Especially in relation to the proposition that a market economy tends naturally to restore itself to full employment after temporary shocks.
title: The General Theory of Employment, Interest and Money
paragraph_text: One of the highest recorded instrumented Mach numbers attained for a propeller aircraft is the Mach 0.891 for a Spitfire PR XI, flown during dive tests at the Royal Aircraft Establishment, Farnborough in April 1944. The Spitfire, a photo - reconnaissance variant, the Mark XI, fitted with an extended 'rake type' multiple pitot system, was flown by Squadron Leader J.R. Tobin to this speed, corresponding to a corrected true airspeed (TAS) of 606 mph. In a subsequent flight, Squadron Leader Anthony Martindale achieved Mach 0.92, but it ended in a forced landing after over - revving damaged the engine.
title: Sound barrier
paragraph_text: The Mach number is named after Austrian physicist and philosopher Ernst Mach, and is a designation proposed by aeronautical engineer Jakob Ackeret. As the Mach number is a dimensionless quantity rather than a unit of measure, with Mach, the number comes "after" the unit; the second Mach number is "Mach2" instead of "2Mach" (or Machs). This is somewhat reminiscent of the early modern ocean sounding unit "mark" (a synonym for fathom), which was also unit-first, and may have influenced the use of the term Mach. In the decade preceding faster-than-sound human flight, aeronautical engineers referred to the speed of sound as "Mach's number", never "Mach 1".
title: Mach number
paragraph_text: He studied mathematics and physics at the Charles University in Prague, and after graduating he became an assistant to professor Ernst Mach. After obtaining his doctorate in Prague in 1873/1874 he came to Zagreb (at the time also part of Austria-Hungary) and founded the Physics Cabinet at the Faculty of Philosophy in 1875.
title: Vinko Dvořák
paragraph_text: Speed Racer, also known as Mach GoGoGo (Japanese: マッハ GoGoGo, Hepburn: Mahha GōGōGō), is a Japanese media franchise about automobile racing. Mach GoGoGo was originally serialized in print in Shueisha's 1966 Shōnen Book. It was released in tankōbon book form by Sun Wide Comics, and later re-released in Japan by Fusosha. Adapted into anime by Tatsunoko Productions, its 52 episodes aired on Fuji TV from April 1967 to March 1968. The anime was later re-broadcast on Tokyo MX from July 1 to September 25, 2008.
title: Speed Racer
paragraph_text: Josef Mach (25 February 1909 in Prostějov – 7 July 1987 in Prague) was a Czech actor, screenwriter and film director.
title: Josef Mach
paragraph_text: Magbass Is a farming town in Tonkolili District in the Northern Province of Sierra Leone. Magbass is located about 55 miles from Freetown. The town is home to the Magbass Sugar Complex, one of the largest sugar producing plantation in West Africa . The factory provides employment for a number of people within Tonkolili District and across Sierra Leone .
title: Magbass
paragraph_text: The Fresnel number ("F"), named after the physicist Augustin-Jean Fresnel, is a dimensionless number occurring in optics, in particular in scalar diffraction theory.
title: Fresnel number
paragraph_text: The Gudermannian function, named after Christoph Gudermann (1798–1852), relates the circular functions and hyperbolic functions without explicitly using complex numbers.
title: Gudermannian function
paragraph_text: Full - time employment is employment in which a person works a minimum number of hours defined as such by his / her employer. Full - time employment often comes with benefits that are not typically offered to part - time, temporary, or flexible workers, such as annual leave, sickleave, and health insurance. Part - time jobs are mistakenly thought by some to not be careers. However, legislation exists to stop employers from discriminating against part - time workers so this should not be a factor when making decisions on career advancement. They generally pay more than part - time jobs per hour, and this is similarly discriminatory if the pay decision is based on part - time status as a primary factor. The Fair Labor Standards Act (FLSA) does not define full - time employment or part - time employment. This is a matter generally to be determined by the employer (US Department of Labor). The definition by employer can vary and is generally published in a company's Employee Handbook. Companies commonly require from 35 to 40 hours per week to be defined as full - time and therefore eligible for benefits.
title: Full-time
paragraph_text: Euler's identity is named after the Swiss mathematician Leonhard Euler. It is considered to be an exemplar of mathematical beauty as it shows a profound connection between the most fundamental numbers in mathematics.
title: Euler's identity
paragraph_text: Zeckendorf's theorem, named after Belgian mathematician Edouard Zeckendorf, is a theorem about the representation of integers as sums of Fibonacci numbers.
title: Zeckendorf's theorem
paragraph_text: In mathematics, the Riemann sphere, named after Bernhard Riemann, is a model of the extended complex plane, the complex plane plus a point at infinity. This extended plane represents the extended complex numbers, that is, the complex numbers plus a value ∞ for infinity. With the Riemann model, the point "∞" is near to very large numbers, just as the point "0" is near to very small numbers.
title: Riemann sphere
paragraph_text: Mach bands is an optical illusion named after the physicist Ernst Mach. It exaggerates the contrast between edges of the slightly differing shades of gray, as soon as they contact one another, by triggering edge-detection in the human visual system.
title: Mach bands
paragraph_text: The MiG-25 underwent substantial design sacrifices in order to achieve high speed, altitude and rate of climb. However, it lacked maneuverability at interception speeds and was difficult to fly at low altitudes. The MiG-25's speed was limited to Mach 2.83, but it could reach a maximum speed of Mach 3.2 or more with the risk of engine damage.
title: Mikoyan MiG-31
paragraph_text: In theoretical physics, particularly in discussions of , Mach's principle (or Mach's conjecture) is the name given by Einstein to an imprecise hypothesis often credited to the physicist and philosopher Ernst Mach. The idea is that the existence of absolute rotation (the distinction of local inertial frames vs. rotating reference frames) is determined by the large-scale distribution of matter, as exemplified by this anecdote:
title: Mach's principle
paragraph_text: On July 26, Truman mandated the end of hiring and employment discrimination in the federal government, reaffirming FDR's order of 1941.:40 He issued two executive orders on July 26, 1948: Executive Order 9980 and Executive Order 9981. Executive Order 9980, named Regulations Governing for Employment Practices within the Federal Establishment, instituted fair employment practices in the civilian agencies of the federal government. The order created the position of Fair Employment Officer. The order "established in the Civil Service Commission a Fair Employment Board of not less than seven persons." Executive Order 9981, named Establishing the President's Committee on Equality of Treatment and Opportunity in the Armed Services, called for the integration of the Armed Forces and the creation of the National Military Establishment to carry out the executive order.
title: Affirmative action in the United States
paragraph_text: Psycho is a 1960 American psychological horror film directed and produced by Alfred Hitchcock, and written by Joseph Stefano, starring Anthony Perkins, Janet Leigh, John Gavin, Vera Miles and Martin Balsam, and was based on the 1959 novel of the same name by Robert Bloch. The film centers on the encounter between a secretary, Marion Crane (Leigh), who ends up at a secluded motel after stealing money from her employer, and the motel's disturbed owner - manager, Norman Bates (Perkins), and its aftermath.
title: Psycho (1960 film)

Reasoning steps:
What is Mach number named after? >>>> Ernst Mach
Ernst Mach >> employer >>>> Charles University

Answer: spans: Charles University