Tarski Geometries of dimension N or more

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Thierry Arnoux

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Nov 23, 2019, 4:33:27 AM11/23/19
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Dear fellow Metamathers,

When introducing new concepts in Metamath, as a convention, I always try to define new classes, which are then either class builders, functions or operations, instead of introducing a new syntax notation (BTW, where is this "convention" written down? I think this is not exactly what the "new definitions infrequent" covers).

However I'm a bit stuck with "TarskiGLD", the Tarski geometries of dimension N or more. I initially wanted them defined as a function of N, however I believe the resulting set is a proper class, not allowing me to define it as a map-to function. Is there any trick I can use there?

I thought about restricting to structures, like ` TarskiGLD = ( N e. NN |-> { g e. dom Struct | ... } ) ` , but dom Struct is also a proper class.

Right now, my latest pull request has a new syntax notation "TarskiGLD ( N )" for that concept, but I would be interested in any suggestion!

Thanks in advance for your insight!

_
Thierry

Thierry Arnoux

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Nov 23, 2019, 4:50:29 AM11/23/19
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Dear fellow Metamathers,

I think I've got it: I'll define "TarskiGLD" as a relation, where ` G TarskiGLD N ` holds whenever ` G ` is a Tarskian geometry of dimension ` N ` or more. This does the trick without introducing any new syntax.

Sorry for answering so quickly, and to my own post!

_
Thierry

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Mario Carneiro

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Nov 23, 2019, 4:57:01 AM11/23/19
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Yes. That.

Alexander van der Vekens

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Nov 23, 2019, 5:08:35 AM11/23/19
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Often it helps to formulate a problem so that others can understand it to find the solution by oneself ;-)

Alexander

On Saturday, November 23, 2019 at 10:50:29 AM UTC+1, Thierry Arnoux wrote:

Dear fellow Metamathers,

I think I've got it: I'll define "TarskiGLD" as a relation, where ` G TarskiGLD N ` holds whenever ` G ` is a Tarskian geometry of dimension ` N ` or more. This does the trick without introducing any new syntax.

Sorry for answering so quickly, and to my own post!

_
Thierry


On 23/11/2019 17:33, Thierry Arnoux wrote:

Dear fellow Metamathers,

When introducing new concepts in Metamath, as a convention, I always try to define new classes, which are then either class builders, functions or operations, instead of introducing a new syntax notation (BTW, where is this "convention" written down? I think this is not exactly what the "new definitions infrequent" covers).

However I'm a bit stuck with "TarskiGLD", the Tarski geometries of dimension N or more. I initially wanted them defined as a function of N, however I believe the resulting set is a proper class, not allowing me to define it as a map-to function. Is there any trick I can use there?

I thought about restricting to structures, like ` TarskiGLD = ( N e. NN |-> { g e. dom Struct | ... } ) ` , but dom Struct is also a proper class.

Right now, my latest pull request has a new syntax notation "TarskiGLD ( N )" for that concept, but I would be interested in any suggestion!

Thanks in advance for your insight!

_
Thierry

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