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Re: FullForm puzzle.

• To: mathgroup at smc.vnet.net
• Subject: [mg106296] Re: [mg106248] FullForm puzzle.
• From: Bob Hanlon <hanlonr at cox.net>
• Date: Thu, 7 Jan 2010 02:33:45 -0500 (EST)
• Reply-to: hanlonr at cox.net

Because while they are functionally equivalent they are only apparently identical. The output (how it displays) is the formatting of the underlying FullForm (i.e., how it is represented inside Mathematica). Two different FullForm expressions can have the same output formatting. 

They are equivalent:

Reduce[LessEqual[2, x, 3]] === 
 Inequality[2, LessEqual, x, LessEqual, 3]

True


Bob Hanlon

---- Jack L Goldberg 1 <jackgold at umich.edu> wrote: 

=============
I wonder why two apparently identical output forms have different FullForms.

(1)  FullForm[ 2<= x< =3] returns LessEqual[2,x,3]

while

(2) Reduce[ 2<=x && x<=3 ] returns 2 <= x <= 3 whose FullForm is
Inequality[2,LessEqual,x,LessEqual,3].

Any thoughts?

Jack