
Carter Lyons: Good morning! I guess it goes without saying (but I will anyway) that my conjecture yesterday about problem 8.3 was way off base. Sorry about that! Janet McShane has joined this chat. Dominic Soda: is qt running? Juli Rainbolt: vnc started - stand by on video and audio drvazz has joined this chat. Ayan Mahalanobis has joined this chat. Ayan Mahalanobis: Thanks! Juli Rainbolt: vnc and quicktime have started sklarjk has joined this chat. Donna Nonnenkamp: vnc is the same ip as yesterday 165.134.131.27 The quicktime for audio is rtsp://165.134.240.33/audio0717a.sdp and the quicktime for video is rtsp://165.134.240.33/video0717a.sdp janetlbeery has joined this chat. 10:00AM Juli Rainbolt: questions? Dominic Soda: qt problems here again see you shortly Dominic Soda has left this chat. Carter Lyons: I am still trying toget QT going. 10:05AM Donna Nonnenkamp: Carter- do you need help? Dominic Soda has joined this chat. Donna Nonnenkamp: Hi Dominic Carter Lyons: No. I forgot to turn up the volume on myspeaker. I am fine now. Dominic Soda: qt is back thanks Donna Nonnenkamp: Good brooksbankpa: not such a problem here but it's often difficult to see what a list of vectors contains; the Display command is useful. e.g. Display(Elements(V)); Ayan Mahalanobis: can we have some lattice structure on the subspaces. 10:10AM Ayan Mahalanobis: In Xgap Ayan Mahalanobis: Ok! brooksbankpa: I've not used it in years but it would make sense that it could. Tracy Hamilton has joined this chat. Ayan Mahalanobis: Sound is out. Donna Nonnenkamp: Tracy The quicktime for audio is rtsp://165.134.240.33/audio0717a.sdp and the quicktime for video is rtsp://165.134.240.33/video0717a.sdp drvazz: not here Silvia La Falce: audio is fine her brooksbankpa: I'm fine. Tracy Hamilton: fine Dominic Soda: yes qt is fine drvazz: I mean, sound fine here Jim Woeppel: Sound OK sklarjk: I can hear fine. Ken Yanosko: i hear you Carter Lyons: Sound is okayhere. Robert Talbert: Sound and vid is fine here janetlbeery: yes, fine Meral Arnavut: I hear you! Ayan Mahalanobis: I am fine. Tracy Hamilton: sorry i was late -- traffic How far into section 11 are we? Carter Lyons: The bottom of the GAP window is not visible. Can you shrink that window slightly? Silvia La Falce: Display(Elements(D)); gave a nice list of Silvia La Falce: subspaces with generators 10:15AM Donna Nonnenkamp: Carter is that better? Math and Computer Science: Tracy - he is taking about the text in Section 11 - he has not gotten to the project yet. Carter Lyons: I cannot control the scroll onyour screen. Should I be able to do that? Tracy Hamilton: thanks Math and Computer Science: taking should have been "talking" Carter Lyons: Got it. brooksbankpa: (p^3-1)/(p-1) 10:20AM drvazz: =p^2+p+1 Tong Wu has left this chat. Silvia La Falce: there are p^3-1 generators and Silvia La Falce: each subspace uses p-1 of them Tong Wu has joined this chat. brooksbankpa: same brooksbankpa: hyperplanes and points are interchangeable. Dominic Soda: could you scroll back to Display when you get a chance brooksbankpa: not really 10:25AM Dominic Soda: thanks brooksbankpa: there are some useful commands for elementary linear algebra -- are you going to touch on this topic at some stage? Dominic Soda: yes brooksbankpa: will do then brooksbankpa: they're worth knowing I think -- and easy 10:30AM Robert Talbert: Question -- I typed in "Int(Z(2))" and it gave back "1" as Juli said, but "Int(Z(2^2))" gives an error message, and so does "Int(Z(4))". Is there a simple explanation for that? Ayan Mahalanobis: Probably they are not integers but polynomials. Ayan Mahalanobis: Does GAP look at the field extension as polynomials? brooksbankpa: Z(4) is a generator of the field GF(4); you can only get integers for elements of the ground field GF(2) Math and Computer Science: or equivalent representation Ayan Mahalanobis: Do we knoe ehat representation? 10:35AM Ayan Mahalanobis: knoe=know & ehat=what Math and Computer Science: Donna is going to paste in a link for Allen Hibbard's algebra resources Donna Nonnenkamp: http://www.central.edu/AlgebraResources/ 10:40AM Dominic Soda: Do your students have linear algebra before abstract algebra? Math and Computer Science: yes Ayan Mahalanobis: No way to see the elements in algebraic extension. Dominic Soda: amen! brooksbankpa: I tried using some of this stuff yesterday to factor x^2+1 of the Gaussian Rationals, but didn't have much success. 10:45AM Math and Computer Science: I've just sent out an email to the list which discusses Ayan's question Math and Computer Science: It's a response to a Q in the GAP forum from 1994 Math and Computer Science: by Alexander Hulpke, again 10:50AM Donna Nonnenkamp: changiing tape Ayan Mahalanobis: How will one do arithmetic inside a finite field? Donna Nonnenkamp: new tape installed thanks Ayan Mahalanobis: there is a vector space structure with finite field extension. Is this the same we are talking about? 10:55AM brooksbankpa: yes -- I'll include a discussion of this in the email I send out later. Ayan Mahalanobis: So those nasty looking elements are vectors? brooksbankpa: yes one can easily regard GF(p^k) as a vector space over its prime field GF(p) in GAP. brooksbankpa: by the way, arithmetic is performed in finite field using "look-up tables" or "Zech logarithm" tables; that's part of the reason why GAP can't handle large finite fields. Ayan Mahalanobis: No normal basis or polynomial basis! 11:00AM brooksbankpa: do you use other systems for linear algebra? Math and Computer Science: Maple brooksbankpa: thanks. brooksbankpa: I will do, thanks. Dominic Soda: why not GAP? drvazz: Mathematica is nice for linear algebra, too, but the syntax for GAP is closer to Maple syntax janetlbeery: MATLAB's wonderful for linear algebra. Dominic Soda: thanks 11:10AM Carter Lyons: Can you DISPLAY this F? It wold be a good way to see the elements of the factor ring. 11:15AM Robert Talbert: "Display(F)" gives "Field([ (a) ])" brooksbankpa: (a) is the primitive element here brooksbankpa: i.e. the generator of the multiplicative group brooksbankpa: try r:=PrimitiveElement( F ); brooksbankpa: now, as Russell suggests, you can regard elements as powers of r. For example r^2 returns (a^2) Tong Wu: Would you want the student to discover one of the irreducible polynomials from the list of above (factors of x^27 - 1? Robert-TSU Ayan Mahalanobis: Well in a teaching situation that is probably not feasible. It is doing things backward. 11:20AM brooksbankpa: Again, KnownAttributesOfObject( F ), tells the students what GAP knows about the object he/she has constructed. brooksbankpa: it's essentially all it knows about ANY field, so you really can compute with it.Back to Home Page
This PREP workshop is made possible by the NSF grant DUE: 0089005