From: zuhair on 1 May 2010 12:40 This is the continuation of the same topic that I've lastly posted to this Usenet. Seeing the dot system I would like to make some modification on the system that I proposed in the previous post. Alternative Notation of FOL(=,membership) (1) Logical connectives Negation ~ Disjunction | Implication > Bi-conditional <> Conjunction No symbol, jusxtapositionning the formulae. so QP stands for Q and P. (2) Quantifiers Existential quantifier _ so _x stands for 'there exist x'. Unique Existential quantifier ! !x stands for 'there exist only one x'. Universal quantifier no symbol only write the quantified variable. Example: x _y is read as: for all x there exist y The quantifiers need not be actually written if writing them makes no difference to the meaning of the formula Example: writing the Extensionality axiom (see below) The order of the quantifiers if x is written to the left of y for example then the order of quantification is the same For example _x ~yx this is the Empty set axiom, it is read as There exist x for all y not y in x. We don't need to write _x y ~yx because the y in the middle add nothing to the meaning of the sentence, so it is redundant. However this method is tricky, for example ~yx alone would be read as for all y for all x not y in x. also _y yx is read as, there exist y for all x y in x. While x _y ~yx is read as: For all x there exist y not y in x. (3) Quantification strings To write for example Exist x0, Exist x1,...,Exist xn which is usually written as Exist x0,...,xn We write it here as: _x0,,,xn while, for all x0, for all x1,..., for all xn is written as x0,,,xn while Exist x0 for all x1, for all x2,...,for all xn is written as: _x0; x1...xn so a semi-colon separates x0 from x1. (4) Primitives: Membership No symbol only juxtapositioning the two symbols. Example: xy mean x is a member of y Identity = (4) Functions: the same traditional way of symbolization F(x1,,,xn) The ordered pair is written as (x,y). f: A -> B means f is a function from the domain A to the co-domain B. (5) Predicates: written in the usual manner. (6) The class builder notation { : } or { | } is to remain as it is. (7) Dots notations, these serve to determine the sequence of processing the formulas in a certain formula, so they replace brackets in performing that function. Generally the flow is from the smaller power dot notations to the larger ones. A dot notation is to be placed always on the left of a connective. we have different powers of dot notations:- .. is a unit power dot notation : is a double power dot notation :. is a triple power dot notation :: is a quadruple power dot notation ::. is a five unit power dot notation and so on, the power of a dot notation is determined directly by the number of dots in it. of course the first connectives to be processed are those who do not have any dot notation on the left of them. Examples: P|Q.|Q:>D.S<>K this would be ( (P|Q) | Q ) > (D and (S<>K)) so instead of 8 brackets, we only have three controller symbols. Another example: P|Q:.|Q:>D.S<>K this would be (P|Q) | (Q>(D and (S<>K))) Example: t _x yt::.<> w _k uw::<> u is a wiener ordered pair i _s,r isru > i subset k: j _p,q jpqu 0eq. > j=x:. > yw is the abbreviation of for all t Exist x for all y ( y e t <-> for all w ( Exist k for all u ( u e w <-> (u is a wiener ordered pair & for all i Exist sr (iesereu -> i subset k)& for all j Exist pq ((jepeqeu & 0eq) -> j=x))) -> yew)). As one can see, there is a great difference in the size, and clarity of the two formulas. As a last example, I shall re-write the formulas of the axioms of ZF set theory: _______________________________________________ Extensionality: zx<>zy > x=y Foundation: x _yx > _yx _cy cx Empty: _x ~yx Pairing: a,b _x yx.<> y=a|y=b Union: a _x yx <> _z yza Power: a _x yx<> zy>za Separation: a _x yx.<> yaQ Replacement: x!yQ> a _b zb <>_xaQ(x,z) _______________________________________________ This technique greatly abbreviate fol(=,membership), and it is clearer, more neat and do not have strange looking symbols in them. Isn't it? Zuhair
From: MoeBlee on 1 May 2010 13:22 On May 1, 9:42 am, zuhair <zaljo...(a)gmail.com> wrote: > The quantifiers need not be actually written if writing them > makes no difference to the meaning of the formula > > Example: writing the Extensionality axiom (see below) [...] > Extensionality: zx<>zy > x=y WRONG Az(zex <-> zey) -> x=y is NOT equivalent with Az((zex <-> zey) -> x=y) Please get a book on the basics of this subject. MoeBlee
From: zuhair on 1 May 2010 13:26 On May 1, 11:42 am, zuhair <zaljo...(a)gmail.com> wrote: > This is the continuation of the same topic that I've lastly posted to > this Usenet. > > Seeing the dot system I would like to make some modification on the > system that I proposed in the previous post. > > Alternative Notation of FOL(=,membership) > > (1) Logical connectives > > Negation ~ > > Disjunction | > > Implication > > > Bi-conditional <> > > Conjunction No symbol, jusxtapositionning the formulae. > > so QP stands for Q and P. > > (2) Quantifiers > > Existential quantifier _ > > so _x stands for 'there exist x'. > > Unique Existential quantifier ! > > !x stands for 'there exist only one x'. > > Universal quantifier no symbol only write the quantified variable. > > Example: > > x _y is read as: for all x there exist y > > The quantifiers need not be actually written if writing them > makes no difference to the meaning of the formula > > Example: writing the Extensionality axiom (see below) > > The order of the quantifiers > > if x is written to the left of y for example > then the order of quantification is the same > > For example > > _x ~yx > > this is the Empty set axiom, it is read as > > There exist x for all y not y in x. > > We don't need to write > > _x y ~yx > > because the y in the middle add nothing to the meaning > of the sentence, so it is redundant. > > However this method is tricky, for example > > ~yx alone would be read as for all y for all x not y in x. > > also > > _y yx > > is read as, there exist y for all x y in x. > > While > > x _y ~yx is read as: > > For all x there exist y not y in x. > > (3) Quantification strings > > To write for example > > Exist x0, Exist x1,...,Exist xn > > which is usually written as > > Exist x0,...,xn > > We write it here as: > > _x0,,,xn > > while, for all x0, for all x1,..., for all xn > > is written as > > x0,,,xn > > while Exist x0 for all x1, for all x2,...,for all xn > > is written as: > > _x0; x1,,,xn > > so a semi-colon separates x0 from x1. > > (4) Primitives: > > Membership No symbol > > only juxtapositioning the two symbols. > > Example: xy mean x is a member of y > > Identity = > > (4) Functions: the same traditional way of symbolization > > F(x1,,,xn) > > The ordered pair is written as (x,y). > > f: A -> B means f is a function from the domain A to the > co-domain B. > > (5) Predicates: written in the usual manner. > > (6) The class builder notation { : } or { | } > is to remain as it is. > > (7) Dots notations, these serve to determine the sequence of > processing the formulas in a certain formula, so they > replace brackets in performing that function. > > Generally the flow is from the smaller power dot notations > to the larger ones. > > A dot notation is to be placed always on the left of a connective. > > we have different powers of dot notations:- > > . is a unit power dot notation > > : is a double power dot notation > > :. is a triple power dot notation > > :: is a quadruple power dot notation > > ::. is a five unit power dot notation > > and so on, the power of a dot notation is determined directly > by the number of dots in it. > > of course the first connectives to be processed are > those who do not have any dot notation on the left of them. > > Examples: > > P|Q.|Q:>D.S<>K > > this would be ( (P|Q) | Q ) > (D and (S<>K)) > > so instead of 8 brackets, we only have three controller symbols. > > Another example: > > P|Q:.|Q:>D.S<>K > > this would be > > (P|Q) | (Q>(D and (S<>K))) > > Example: > > t _x yt::.<> w _k uw::<> u is a wiener ordered pair > i _s,r isru > i subset k: > j _p,q jpqu 0eq. > j=x:. > > yw > > is the abbreviation of > > for all t Exist x for all y ( y e t <-> for all w > ( Exist k for all u ( u e w <-> > (u is a wiener ordered pair & > for all i Exist sr (iesereu -> i subset k)& > for all j Exist pq ((jepeqeu & 0eq) -> j=x))) > -> yew)). > > As one can see, there is a great difference in the size, and > clarity of the two formulas. > > As a last example, I shall re-write the formulas of the axioms > of ZF set theory: > > _______________________________________________ > > Extensionality: zx<>zy > x=y > > Foundation: x _yx > _yx _cy cx > > Empty: _x ~yx > > Pairing: a,b _x yx.<> y=a|y=b > > Union: a _x yx <> _z yza > > Power: a _x yx<> zy>za > > Separation: a _x yx.<> yaQ > > Replacement: x!yQ> a _b zb <>_xaQ(x,z) Infinity: _x 0x yx > U(y,{y})x were z=U(y,{y}):<> uz.<> uy|u=y > _______________________________________________ > > This technique greatly abbreviate fol(=,membership), and it is > clearer, more neat and do not have strange looking symbols in them. > > Isn't it? > > Zuhair
From: zuhair on 1 May 2010 13:36 On May 1, 12:22 pm, MoeBlee <jazzm...(a)hotmail.com> wrote: > On May 1, 9:42 am, zuhair <zaljo...(a)gmail.com> wrote: > > > The quantifiers need not be actually written if writing them > > makes no difference to the meaning of the formula > > > Example: writing the Extensionality axiom (see below) > > [...] > > > Extensionality: zx<>zy > x=y > > WRONG > > Az(zex <-> zey) -> x=y > > is NOT equivalent with > > Az((zex <-> zey) -> x=y) > > Please get a book on the basics of this subject. > > MoeBlee hmmm...., it seems that we must apply the dot notation to be sometimes on the right of quantifiers also. like: z.zx<>zy:> y=x Zuhair
From: zuhair on 1 May 2010 14:02 On May 1, 12:22 pm, MoeBlee <jazzm...(a)hotmail.com> wrote: > On May 1, 9:42 am, zuhair <zaljo...(a)gmail.com> wrote: > > > The quantifiers need not be actually written if writing them > > makes no difference to the meaning of the formula > > > Example: writing the Extensionality axiom (see below) > > [...] > > > Extensionality: zx<>zy > x=y > > WRONG > > Az(zex <-> zey) -> x=y > > is NOT equivalent with > > Az((zex <-> zey) -> x=y) > > Please get a book on the basics of this subject. > > MoeBlee I underestimated quantification. I need to look into that closely. Thanks Zuhair
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