05 DM PredicateLogic 0803 01

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Discrete Mathematics - Predicate Logic I

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  • Module #1 - Logic

    3/8/2013 11

    HY118-

    Kees van

    Deemter,

    University of Aberdeen

    , 08/03/2013

    . e-mail: [email protected]

  • Module #1 - Logic

    3/8/2013 22

  • Module #1 - Logic

    3/8/2013 33

    /

    , , ,

    ,

    /

    (x:=a)

  • Module #1 - Logic

    3/8/2013 44

  • Module #1 - Logic

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    (x,y)= O x y

    x y (x,y)

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    3/8/2013 66

  • Module #1 - Logic

    3/8/2013 77

    (x,y)= O x y

    y x (x,y)

  • Module #1 - Logic

    3/8/2013 88

    B(x,y)= x y,

    :

  • Module #1 - Logic

    3/8/2013 99

    x(y (x,y))=

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

  • Module #1 - Logic

    3/8/2013 1010

    x(y (x,y))= ,

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

  • Module #1 - Logic

    3/8/2013 1111

    x(y (x,y))= ,

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

  • Module #1 - Logic

    3/8/2013 1212

    x(y (x,y))= ,

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

  • Module #1 - Logic

    3/8/2013 1313

    x(y (x,y))= ,

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

  • Module #1 - Logic

    3/8/2013 1414

    x(y (x,y))= ,

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

  • Module #1 - Logic

    3/8/2013 1515

    x(y (x,y))= ,

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

  • Module #1 - Logic

    3/8/2013 1616

    x(y (x,y))= ,

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

  • Module #1 - Logic

    3/8/2013 1717

    x(y (x,y))= ,

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

  • Module #1 - Logic

    3/8/2013 1818

    x(y (x,y))= ,

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

    x(y (x,y))=

    y(x (x,y))=

  • Module #1 - Logic

    P(x,y)=y

  • Module #1 - Logic

    P(x,y)=y

  • Module #1 - Logic

    P(x,y)=y

  • Module #1 - Logic

    P(x,y)=y

  • Module #1 - Logic

    P(x,y)=y

  • Module #1 - Logic

    P(x,y)=y

  • Module #1 - Logic

    P(x,y)=y

  • Module #1 - Logic

    3/8/2013 (c)2001-2004, Michael

    P. Frank

    26

    ..

    ( );

    . ,

    http://en.wikipedia.org/wiki/Empty_domain . :

    x .

    x .

    ..

    (Free Logic):

    http://en.wikipedia.org/wiki/Free_logic

    ,

    .

    Topic #3 Predicate Logic

  • Module #1 - Logic

    3/8/2013 2727

    ...

    P=

    D .

    Q(x) = x

    P : x Q(x)

    ;

  • Module #1 - Logic

    3/8/2013 2828

    ...

    P=

    D .

    Q(x) = x

    P : x Q(x)

    ;

    , , ...

    , !

  • Module #1 - Logic

    3/8/2013 2929

    o ;

    P=

    D ( )

    Q(x) = x

    (x) = x

    P : x ((x) Q(x))

    ;

    , , ...

    , !

  • Module #1 - Logic

    3/8/2013 (c)2001-2004, Michael

    P. Frank

    30

    ..

    1. x(y R(x,y))

    2. y(x R(x,y))

    3. x(y R(x,y))

    3 2 .

    2 , 1

    :

    3 2

    2 1

    Topic #3 Predicate Logic

  • Module #1 - Logic

    3/8/2013 3131

    , ..

    , ..,

    x>0 P(x)

    x , P(x).

    ;

  • Module #1 - Logic

    3/8/2013 3232

    , ..

    , ..,

    x>0 P(x)

    x , P(x).

    ;

    x (x>0 P(x))

  • Module #1 - Logic

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    x>0 P(x) :

    x ,

    P(x).

    x>0 P(x) ;

    =???

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    x>0 P(x) :

    x ,

    P(x).

    x>0 P(x) ;

    =x (x>0 P(x))

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    x>0 P(x) x , P(x).

    =x (x>0 P(x)) x>0 P(x)

    x , P(x).

    =x (x>0 P(x))

  • Module #1 - Logic

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    x (x>0 P(x)) ; ; ; x , P(x).

    x (x>0 P(x)) ; ; ;

    x x>0 P(x)

    ... x

  • Module #1 - Logic

    3/8/2013 3737

    . (D). 118.

    (x) / x /

    (x) / x /

    1. x ((x) (x))

    2. x ((x) (x))

    3. x ((x) (x))

    4. x ((x) (x))

  • Module #1 - Logic

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    1. x ((x) (x))

    2. x ((x) (x))

    3. x ((x) (x))

    4. x ((x) (x)) ,

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    4. x ((x) (x)) , , x ((x) (x)) , a, (a) (a) .

    , (a) (a) (a) (a)

    , (4)

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    : ..={a, b, c,} x P(x) P(a) P(b) P(c) x P(x) P(a) P(b) P(c)

    , :x P(x) (x P(x)) x P(x) x P(x) (x P(x)) x P(x)

    ;

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    x P(x) x P(x)

    P(x) x,

    x P(x) x P(x)

    ,

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    :

    x P(x) x P(x) ( P)

    x P(x) x P(x)

    , ( )

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    x y P(x,y) y x P(x,y)

    x y P(x,y) y x P(x,y)

  • Module #1 - Logic

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    :

    xyz P(x,y,z) . x y z P(x,y,z)

    xyz P(x,y,z) . x y z P(x,y,z)

  • Module #1 - Logic

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    x (P(x) Q(x)) (x P(x)) (x Q(x))

    x (P(x) Q(x)) (x P(x)) (x Q(x))

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    x (P(x) Q(x)) (x P(x)) (x Q(x))

    x (P(x) Q(x)) (x P(x)) (x Q(x))

    ;

    x (P(x) Q(x)) ((x P(x)) (x Q(x));

    ?

  • Module #1 - Logic

    3/8/2013 4747

    ;

    x (P(x) Q(x)) (x P(x)) (x Q(x)) ;

    !!!

    (. )

    P(x): x 24

    Q(x): x 4

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    x (P(x) Q(x)) (x P(x)) (x Q(x)) ;

    P(x): x 24

    Q(x): x 4

    x (P(x) Q(x)) =

    24/4 4/3 [FALSE]

    (x P(x)) (x Q(x)) =

    24/4

    4/3 [ TRUE]