Skip to main content
added 38 characters in body
Source Link
Alexandre Eremenko
  • 91.8k
  • 9
  • 259
  • 429

A real-valued function $u\geq 0$ such that $\log u$ is subharmonic is called logarithmically subharmonic. One easy theorem is that the sum of logarithmically subharmonic functions is also logarithmically subharmonic. (This can be proved by computation of the Laplacian). It follows that logarithmically subharmonic functions form a convex cone. Moreover,The pointwise maximum of several logarithmically subharmonic functions is logarithmically subharmonic. Moreover, the class is closed with respect to certain limits. Evidently, in dimension 2, this class contains all functions of the form $|f|$, where $f$ is analytic, and one can show that this is the minimal class containing all $|f|$$|f|^\alpha, \alpha>0$ where $f$ is analytic, and closed with respect to the mentioned operations$L^1_{\mathrm{loc}}$ limits.

A real-valued function $u\geq 0$ such that $\log u$ is subharmonic is called logarithmically subharmonic. One easy theorem is that the sum of logarithmically subharmonic functions is also logarithmically subharmonic. (This can be proved by computation of the Laplacian). It follows that logarithmically subharmonic functions form a convex cone. Moreover, pointwise maximum of several logarithmically subharmonic functions is logarithmically subharmonic. Moreover, the class is closed with respect to certain limits. Evidently, in dimension 2, this class contains all functions of the form $|f|$, where $f$ is analytic, and one can show that this is the minimal class containing all $|f|$ and closed with respect to the mentioned operations.

A real-valued function $u\geq 0$ such that $\log u$ is subharmonic is called logarithmically subharmonic. One easy theorem is that the sum of logarithmically subharmonic functions is also logarithmically subharmonic. (This can be proved by computation of the Laplacian). It follows that logarithmically subharmonic functions form a convex cone. The pointwise maximum of several logarithmically subharmonic functions is logarithmically subharmonic. Moreover, the class is closed with respect to certain limits. Evidently, in dimension 2, this class contains all functions of the form $|f|$, where $f$ is analytic, and one can show that this is the minimal class containing all $|f|^\alpha, \alpha>0$ where $f$ is analytic, and closed with respect to $L^1_{\mathrm{loc}}$ limits.

Source Link
Alexandre Eremenko
  • 91.8k
  • 9
  • 259
  • 429

A real-valued function $u\geq 0$ such that $\log u$ is subharmonic is called logarithmically subharmonic. One easy theorem is that the sum of logarithmically subharmonic functions is also logarithmically subharmonic. (This can be proved by computation of the Laplacian). It follows that logarithmically subharmonic functions form a convex cone. Moreover, pointwise maximum of several logarithmically subharmonic functions is logarithmically subharmonic. Moreover, the class is closed with respect to certain limits. Evidently, in dimension 2, this class contains all functions of the form $|f|$, where $f$ is analytic, and one can show that this is the minimal class containing all $|f|$ and closed with respect to the mentioned operations.