How to check if to equations are the same

I'm looking for method to check if two symbolic equations are the same. e.g:

syms x1, x2, x3;
a = x1 == x2 + x3;
b = x1 - x2 == x3;
isequal(a, b)

isequal always returns false. Is there a method which can verify that the equations are the same?

Answer 1

[Star Strider]

Use the Symbolic Math Toolbox isAlways funciton:

syms x1 x2 x3
a = x1 == x2 + x3;
b = x1 - x2 == x3;
Q = isAlways(a == b)

Q =
     1

[Randolph Brockman]

My savior!