Re: [Hol-info] where is the higher order logic in HOL?

2015-11-18 Thread Konrad Slind
As Michael said, higher order is all over the place, even if first order reasoning is commonplace. One of my favourite higher order statements is the following encapsulation of Skolemization: SKOLEM_THM; val it = |- ∀P. (∀x. ∃y. P x y) ⇔ ∃f. ∀x. P x (f x): thm Konrad. On Wed, Nov 18, 201

Re: [Hol-info] where is the higher order logic in HOL?

2015-11-18 Thread Michael Norrish
Some of the definitions are higher-order. For example, the universal quantifier has to be higher order because it's a function that takes a predicate as an argument. Even functions like MAP are higher-order because they take functions as arguments. Often metis is capable of proving useful fac

[Hol-info] where is the higher order logic in HOL?

2015-11-18 Thread shengyu shen
Dear all: HOL is a higher order logic theorem prover, while most of the time, we use first order lib such as season and metis, So where is the higher order? Shen -- ___ hol-in

Re: [Hol-info] Definition of Binary Relation in HOL

2015-11-18 Thread Ramana Kumar
Which binary relation? What do you mean? Here's a binary relation that relates natural numbers 1 and 2: val a_binary_relation_def = Define`a_binary_relation x y <=> (x = 1) /\ (y = 2)`; Here's a binary relation that relates two Booleans iff exactly one of them is true: val another_binary_relation

[Hol-info] Definition of Binary Relation in HOL

2015-11-18 Thread Muhammad Nadeem Iqbal
I have a query that how can we define a binary relation in HOL with a specified type? -- ___ hol-info mailing list hol-info@lists.sourceforge.net https://lists.sourceforge.net/lis

Re: [Hol-info] proof structure in Coq

2015-11-18 Thread Mark Adams
Just to be clear, Tactician (only for HOL Light at the moment) goes between the three styles: - g and e - prove with THEN/THENL/etc - Flyspeck's 'prove_by_refinement', which is a hybrid of the above two Mark. on 18/11/15 8:54 AM, Ramana Kumar wrote: > I usually use ">>" instead of literally

Re: [Hol-info] proof structure in Coq

2015-11-18 Thread Ramana Kumar
I usually use ">>" instead of literally "THEN". Arguably that's still too much "shift". Yes I think you're right about tactician - it's for going back and forth between those styles. On 18 November 2015 at 08:41, Freek Wiedijk wrote: > Hi Ramana, > > >Apparently Coq somewhat recently gained the

Re: [Hol-info] proof structure in Coq

2015-11-18 Thread Freek Wiedijk
Hi Ramana, >Apparently Coq somewhat recently gained the ability to be explicit about >proof structure: >http://poleiro.info/posts/2013-06-27-structuring-proofs-with-bullets.html >(Of course that comes naturally when using tacticals like THEN, THEN1, etc.) Not _very_ recently. It was introduced i