Hey there! Sign in to join this conversationNew here? Join for free
Turn on thread page Beta
    • Thread Starter
    Offline

    14
    ReputationRep:
    (for example) I want to write a \not= b \land b \not= c \land c \not= a

    Is there a way to write this using nice fancy notation similar to this

    :

    Its just much nicer than a_i \not= a_j\ \forall a_i,a_j \in{a,b,c} \land i \not= jThanks
    Offline

    22
    ReputationRep:
    (Original post by Johann von Gauss)
    I want to write a \not= b \land b \not= c \land c \not= a

    Is there a way to write this using nice fancy notation similar to this:



    Its just much nicer than a_i \not= a_j\ \forall a_i,a_j \in{a,b,c} \land i \not= j

    Thanks
    http://tex.stackexchange.com/questio...big-and-symbol
    • Study Helper
    Offline

    15
    Study Helper
    Can you not just say, a,b,c are distinct values, or whatever they are.
    Offline

    22
    ReputationRep:
    (Original post by ghostwalker)
    Can you not just say, a,b,c are distinct values, or whatever they are.
    Precisely what I'd do as well - I'd take some English over obscure logic notation if it isn't necessary anyday.
    • Thread Starter
    Offline

    14
    ReputationRep:
    Thanks, do you happen to know what the 'big and' symbol is called? I've never seen it anywhere (except your link), but I can't see any reason it wouldn't be used. That's the only result on Google for "big and" logic symbol - not sure what to search tbh.

    (Original post by Zacken)
    Precisely what I'd do as well - I'd take some English over obscure logic notation if it isn't necessary anyday.
    A sentence in maths feels like an essay to me... painful to write words when I'm itching to do maths

    (Original post by ghostwalker)
    Can you not just say, a,b,c are distinct values, or whatever they are.
    Yes, but I'm asking if I can use this nicer notation (or similar)?
    Offline

    22
    ReputationRep:
    (Original post by Johann von Gauss)
    Thanks, do you happen to know what the 'big and' symbol is called? I've never seen it anywhere (except your link), but I can't see any reason it wouldn't be used


    A sentence in maths feels like an essay to me... painful to write words when I'm itching to do maths
    To each his own, I suppose. :lol:

    I don't think there is a name for it - is there name for the big union operator?
    • Study Helper
    Offline

    15
    Study Helper
    \bigwedge if you want the LaTex. And \bigvee for the "or" equivalent.
    • Thread Starter
    Offline

    14
    ReputationRep:
    Like this? Is this an acceptable way to represent "a,b,c are distinct"?

    \bigwedge_{cyc(a b c)} (a \not= b)
    • Study Helper
    Offline

    15
    Study Helper
    (Original post by Johann von Gauss)
    Like this? Is this an acceptable way to represent "a,b,c are distinct"?

    \bigwedge_{cyc(a b c)} (a \not= b)
    Not something I've every seen.

    Not familiar with the \cyc as some form of indexing, or at all.

    And it doesn't look right to have a,b in both the set you're selecting from and as the terms in the conjunction.

    What are a,b,c?
    • Thread Starter
    Offline

    14
    ReputationRep:
    (Original post by ghostwalker)
    Not something I've every seen.

    Not familiar with the \cyc as some form of indexing, or at all.

    And it doesn't look right to have a,b in both the set you're selecting from and as the terms in the conjunction.

    What are a,b,c?
    AFAIK, cyc(abc) is more informal notation for a cyclic permutation (a to b to c to a), i.e. \sum_{cyc(abc)}f(a,b,c) = f(a,b,c)+f(b,c,a)+f(c,a,b)
    • Study Helper
    Offline

    15
    Study Helper
    (Original post by Johann von Gauss)
    AFAIK, cyc(abc) is more informal notation for a cyclic permutation (a to b to c to a), i.e. \sum_{cyc(abc)}f(a,b,c) = f(a,b,c)+f(b,c,a)+f(c,a,b)
    In that case it seems reasonable.
    Offline

    11
    ReputationRep:
    (Original post by Johann von Gauss)
    Like this? Is this an acceptable way to represent "a,b,c are distinct"?

    \bigwedge_{cyc(a b c)} (a \not= b)
    Only if it's acceptable to make your intention incomprehensible. All IMHO, of course.
    • Thread Starter
    Offline

    14
    ReputationRep:
    (Original post by atsruser)
    Only if it's acceptable to make your intention incomprehensible. All IMHO, of course.
    Is it not used much at higher levels? I'd assumed more advanced maths would use these kinds of symbols. I'm only an A-level student.

    (Original post by ghostwalker)
    In that case it seems reasonable.
    People on this site use cyc notation a lot:

    http://www.artofproblemsolving.com/c...744_inequality
    Offline

    11
    ReputationRep:
    (Original post by Johann von Gauss)
    Is it not used much at higher levels? I'd assumed more advanced maths would use these kinds of symbols. I'm only an A-level student.
    It may be used in formal logic, but I've not seen it used in "normal" mathematics. I ought to add that I fall into the "use English" camp though; I don't even like \exists, \forall much though.


    People on this site use cyc notation a lot:

    http://www.artofproblemsolving.com/c...744_inequality
    Maybe it's useful in number theory type problems as well. I don't think I could follow an argument which used it too well without writing it all out in full. Maybe I'd get used to it with practise.
    Offline

    18
    ReputationRep:
    (Original post by atsruser)
    Maybe it's useful in number theory type problems as well. I don't think I could follow an argument which used it too well without writing it all out in full. Maybe I'd get used to it with practise.
    It comes up a lot in inequalities questions (BMO/IMO type stuff). You also sometimes see it used in discussion about roots of polynomials, symmetric polys and stuff like that.

    I'd say it's definitely not mainstream though. It's at the level where a fairly well read mathmo would probably have seen it used, but would be unlikely to have used it themselves.

    It's probably no surprise to those who've seen some of my rants about notation that I agree with the people saying "what's wrong with using English?", however...
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: November 11, 2015
Poll
“Yanny” or “Laurel”
Useful resources

Make your revision easier

Maths

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

Equations

How to use LaTex

Writing equations the easy way

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.