A subsheaf 
of a sheaf 
is a sheaf for which each 
is a subset of 
and the restriction maps
are the restrictions of those of 
. For sheaves of groups, rings, or modules, the subsets are
required to be subgroups, subrings, or submodules, respectively.
Subsheaf
See also
Ideal Sheaf, Kernel Sheaf, SheafExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Subsheaf." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Subsheaf.html