Re: Re: Re: equaltity of lists

*To*: mathgroup at smc.vnet.net*Subject*: [mg19175] Re: [mg19147] Re: [mg19092] Re: [mg19036] equaltity of lists*From*: Maarten.vanderBurgt at icos.be*Date*: Tue, 10 Aug 1999 02:52:40 -0400*Sender*: owner-wri-mathgroup at wolfram.com

Kevin, Maybe I do not understand your remark completely. But when I do this on my PC (Mathematica 4.0) I get In[1] := Signature[{a, b, c, d}] Out[1] = 1 In[2] := Signature[{a, b, d, c}] Out[2] = -1 Which is completely in line with the definition of Signature. Canonical order has nothing to do with sameness or equality. Maarten "Kevin J. McCann" <kevinmccann at Home.com> on 06-08-99 05:58:49 AM Subject: [mg19175] [mg19147] Re: [mg19092] Re: [mg19036] equaltity of lists Maarten Agree with you, but then why do you get Signature[{a,b,c,d}] True Signature[{a,b,d,c}] False By the same logic this should not return an answer. Kevin ----- Original Message ----- From: <Maarten.vanderBurgt at icos.be> To: mathgroup at smc.vnet.net Subject: [mg19175] [mg19147] [mg19092] Re: [mg19036] equaltity of lists > Drago, > > You should use > > {a, b} === {b, a} > > when you want False as a result. > > The following I copied from the Mathematica help files. This explains the > difference between '===' and '=='. > > SameQ > ----- > lhs === rhs yields True if the expression lhs is identical to rhs, and > yields False otherwise. > > SameQ requires exact correspondence between expressions, except that it > considers Real numbers equal if their difference is less than the > uncertainty of either of them. > > 2 === 2. gives False. > > e1 === e2 === e3 gives True if all the ei are identical. > > > Equal > ----- > lhs == rhs returns True if lhs and rhs are identical. > > lhs == rhs is used to represent a symbolic equation, to be manipulated > using functions like Solve. > > lhs == rhs returns True if lhs and rhs are identical expressions. > > lhs == rhs returns False if lhs and rhs are determined to be unequal by > comparisons between numbers or other raw data, such as strings. > > Approximate numbers are considered equal if they differ in at most their > last eight binary digits (roughly their last two decimal digits). > > 2 == 2. gives True. > > e1 == e2 == e3 gives True if all the ei are equal. > > > > > Maarten > > > > > > > "Drago Ganic" <drago.ganic at in2.hr> on 03-08-99 07:45:05 PM > > > Subject: [mg19175] [mg19147] [mg19092] [mg19036] equaltity of lists > > > > > Hi !! > > Why don't I get an answer (False) when I ask Mathematica > > {a,b}=={b,a} > > like the one I get with > > {1,2}=={2,1} > False > > Greetings from Croatia, > Drago Ganic > > > > > > > >