SV ASSERTION

I have an assertion with a##3a==b;
‘a’ has both positive and zero values.
But the assertion only compares positive values not zero.
How to pass my assertion for zero values also.

In reply to sheetal saini:

I do not know what you mean by “compares positive values not zero”. The equality operator should work.

Can you give an example? show values and the declarations of a and b.

In reply to sheetal saini:

Do you want to check when a changes, after 3 clock cycles a should be equal to b (or b is equal to a)?

If yes, then you should use something like below.
property ab_value;
$change(a) → ##3 a == b;
endproperty

You may need to make sure about syntax , I may have made a mistake. Thank you.