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NHoldFirst

NHoldFirst
is an attribute which specifies that the first argument to a function should not be affected by N.
Prevent N from affecting the first argument of a function:
Prevent N from affecting the first argument of a function:
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System symbols with the NHoldFirst attribute:
The ^(th) zero of the zeta function on the critical line with the imaginary part greater than :
N does not affect the index :
When the second argument is numeric, N evaluates numerically:
Define an "inverse" for :
Set the NHoldFirst attribute so that remains an integer:
A symbolic representation of an inverse of :
This remains unmodified with N:
With a numeric value of , the function evaluates numerically:
HoldFirst prevents evaluation while NHoldFirst only prevents numerical evaluation:
You can prevent both by setting both attributes:
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