I think it's so that we can use symbols in boolean expressions, like In [2]: x & y Out[2]: x ∧ y
But I think this is a bad design. We should rather have a BooleanSymbol to do this. Aaron Meurer On Jun 8, 2011, at 2:41 PM, krastanov.ste...@gmail.com wrote: > Why is it necessary? -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to sympy@googlegroups.com. To unsubscribe from this group, send email to sympy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.