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1.5.6 Relational and Logical Operators
Relational operators.
This tests whether 10 is less than 7. The result is False.
In[1]:= 10 < 7
Out[1]= 
Not all of these numbers are unequal, so this gives False.
In[2]:= 3 != 2 != 3
Out[2]= 
You can mix < and <=.
In[3]:= 3 < 5 <= 6
Out[3]= 
Since both of the quantities involved are numeric, Mathematica can determine that this is true.
In[4]:= Pi^E < E^Pi
Out[4]= 
Mathematica does not know whether this is true or false.
In[5]:= x > y
Out[5]= 
Logical operations.
Both tests give True, so the result is True.
In[6]:= 7 > 4 && 2 != 3
Out[6]= 
You should remember that the logical operations ==, && and || are all double characters in Mathematica. If you have used the C programming language, you will recognize this notation as being the same as in C.
Mathematica does not know whether this is true or false.
In[7]:= p && q
Out[7]= 
Mathematica leaves this expression unchanged.
In[8]:= (p || q) && !(r || s)
Out[8]= 
You can use LogicalExpand to expand out the terms.
In[9]:= LogicalExpand[ % ]
Out[9]= 
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