A function 
is said to be constructible if some algorithm 
computes it, in binary, within volume 
, i.e., 
. Here, the volume 
is the combined number of active edges during all steps,
which is the number of state-changes needed to run a certain Turing
machine on a particular input.
See also
Computable Function, Rabin's Compression Theorem
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Cite this as:
Weisstein, Eric W. "Constructible Function." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/ConstructibleFunction.html