1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Statement logic, negation

  1. Jan 28, 2009 #1
    1. Negate the following statements

    (i): [tex]\forall[/tex]x[tex]\in[/tex]R [tex]\exists[/tex]y[tex]\in[/tex]R such that x+y=0

    (ii): introduction: Each of us got, let's say, 20 bags of green apples.
    Actual Statement: At least one of us (each) found at least one red apple in at least one bag (each). (Each person and each one of it's bags are treated separately)

    2. Relevant equations/3. The attempt at a solution
    No idea. I'm completely lost here.

    Please help, as I have no idea how to negate complex/multi-element statements.
     
  2. jcsd
  3. Jan 28, 2009 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Welcome to PF!

    Hi test_notagain! Welcome to PF! :smile:

    (have an exists: ∃ and an in: ε and a for-all: ∀ :wink:)

    Let's try (ii) first …

    the opposite of something beginning "At least one of us has …" is "There exists one of us who hasn't …"

    can you go on from there? :smile:
     
  4. Jan 29, 2009 #3
    Re: Welcome to PF!

    Thanx tiny-tim, but I still don't get it cuz there are 3 parts to statement (ii)... And what is the negation of the first one (i)?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Statement logic, negation
  1. Negation statement (Replies: 2)

  2. Negating a Statement (Replies: 2)

Loading...