What is "lyapunov"

Lyapunov is a Russian surname that is sometimes romanized as Ljapunov, Liapunov or Ljapunow. Notable people with the surname include:

• Prokopy Lyapunov (? –1611), Russian statesman
• Zakhary Lyapunov (? – after 1612), Russian statesman, Prokopy Lyapunov's brother
• Mikhail Lyapunov (1820–1868), Russian astronomer
• Aleksandr Lyapunov (1857–1918), Russian mathematician and mechanician
  • Lyapunov equation
  • Lyapunov exponent
  • Lyapunov function
  • Lyapunov fractal
  • Lyapunov stability
  • Lyapunov's central limit theorem
  • Lyapunov vector
  • Lyapunov (crater)
• Sergei Lyapunov (1859–1924), Russian composer
• Boris Lyapunov (1862–1943), Russian expert in Slavic studies
• Alexey Lyapunov (1911–1973), Russian mathematician

Lyapunov is a lunar crater named for Aleksandr Lyapunov that is located along the east-northeastern limb of the Moon, and is viewed from the side by observers on Earth. The eastern rim of this crater just falls into the section of the Moon called the far side, and visibility of this formation is affected by libration.

This crater is attached to the south-southeastern rim of the larger walled plain Rayleigh. It is also attached to the western rim of the much larger walled plain Joliot, a formation that lies entirely on the far side of the Moon. To the south-southwest of Lyapunov is the crater Hubble.

The shape of this crater's rim has been modified due to the large adjacent formations, so that it is somewhat polygonal rather than circular. The rim along the western side is less affected by reshaping, although it too is worn by impact erosion. The ejecta from nearby impacts partly covers the northern and some of the southeastern parts of the interior floor. The former forms a triangular section of rough ground that reaches to the midpoint of the floor. The remainder of the floor is relatively level and marked only by tiny craterlets.

Note that some publications list this crater as "Liapunov".