Relational：Base class for all relation types

1. Rel()：A handy wrapper around the Relational class

from sympy import Relfrom sympy.abc import x, yRel(y, x+x**2, '==')

输出：

y == x**2 + x

2. Eq(a,b)：a == b

from sympy import Eqfrom sympy.abc import x, yEq(y, x+x**2)

3. Ne(a,b)：a != b

4. Lt(a,b)：a < b

5. Le(a,b)：a <= b

6. Gt(a, b)：a > b

7. Ge(a, b)：a >= b