The turnstile is the symbol 
.
In mathematical logic, 
means that the formula 
is syntactically deducible from the assumptions in 
. In the theory of integer partitions,
the notation 
means that 
is a partition of 
.
Turnstile
See also
Deduction, Partition, Sequent CalculusExplore with Wolfram|Alpha
References
Andrews, G. E. The Theory of Partitions. Cambridge, England: Cambridge University Press, 1998.Enderton, H. B. A Mathematical Introduction to Logic. New York: Academic Press, 1972.Cite this as:
Weisstein, Eric W. "Turnstile." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Turnstile.html