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KroneckerDelta

KroneckerDelta
gives the Kronecker delta , equal to 1 if all the are equal, and 0 otherwise.
Construct an identity matrix:
Use in sums to pick out elements:
In[1]:=
Click for copyable input
Out[1]=
 
Construct an identity matrix:
In[1]:=
Click for copyable input
Out[1]//MatrixForm=
 
Use in sums to pick out elements:
In[1]:=
Click for copyable input
Out[1]=
One-argument form:
Multi-argument form:
Arguments can be approximate numbers:
TraditionalForm formatting:
Use in sums to pick out terms:
Generate a banded matrix with two superdiagonals:
Pick out elements:
Reduce an equation containing KroneckerDelta:
The support of KroneckerDelta has measure zero:
KroneckerDelta can stay unevaluated for numeric arguments:
A larger setting for $MaxExtraPrecision can be needed:
Equality testing of the arguments takes numerical precision into account:
Express products of signatures as sums of products of Kronecker deltas:
Special cases for 3D; summation over repeated indices is assumed:
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