Boundary Value Analysis(BVA):
Normally this will be used to validate the numeric text 
boxes(fields).
For example if we take a text box it will accept 
Min(say m) 5 chars -Lower boundary
Max(say n) 9 chars -Upper boundary
here the boundaries are 5 and 9.

    (min-1)4--- 5(min)6 -----7-----8------9(Max)---10(max+1)
      invalid---><---------Valid range---------><=-invalid--
                 |                              |
            Bpundary-1                   Boundary-2

Then now we will check the text box by giving different 
inputs at boundaries
like 
Below 5 it must not accept.
Above 9 it must not accept .
for other conditions we will check like
m+1 is acceptable(because 5+1=6)
m-1 is not acceptable(because5-1=4)
n-1 is acceptable(because 8-1=7)
n+1 is not acceptable(because 9+1=10)
and also we can check the middle values between 5 to 9
The middle values must accept.

The real word example is Password field of yahoo mail
it will accept only some number of min characters
and will accept only some number of mix characters

Ok friends
i think u r clear with this answer


Byeeeee Friends
Rajendra
rajendra_penumalli@yahoo.com

This notation is used to write Size and Range of an object
i.e min
    min-1
    min+1
    max
    max+1
    max-1