Support of Function: Closure of Non-Zero Set

[yifli]

the support of a function is defined as the closure of the set where f is nonzero

my question is why not just define the support as the set where f is nonzero?

thanks

 

[mathman]

the support of a function is defined as the closure of the set where f is nonzero

my question is why not just define the support as the set where f is nonzero?

thanks

It could get messy if the function crosses the axis a lot, like sinx.

 

[Stephen Tashi]

the support of a function is defined as the closure of the set where f is nonzero

It isn't defined that way in all books. Some books define it to be the set where the function is nonzero.