There are several conflicting meanings associated with the notation lgx. In German and Russian literature, the notation lgx is used to mean the common logarithm log_(10)x. This is also the usage recommended by the United States Department of Commerce (Taylor 1995, p. 33).

However, lgx is sometimes identified with the binary logarithm log_2x in some number theoretic literature (and here, log_2x mean the base-2 logarithm, not the nested natural logarithm log_2x=lnlnx as defined by Ivić 2003).

Great care is therefore needed to determine the intended definition for lgx when it is encountered in the wild.

See also

Base, Binary Logarithm, Common Logarithm, e, Ln, Logarithm, Napierian Logarithm, Natural Logarithm, Nested Logarithm

Explore with Wolfram|Alpha


More things to try:


Ivić, A. "On a Problem of Erdős Involving the Largest Prime Factor of n." 5 Nov 2003., B. N. Guide for the Use of the International System of Units (SI). United States Department of Commerce. NIST Special Publication 811, p. 33, 1995.

Referenced on Wolfram|Alpha


Cite this as:

Weisstein, Eric W. "Lg." From MathWorld--A Wolfram Web Resource.

Subject classifications