When do two Prolog terms marry? (Was: The issue with free speech)

From	Mild Shock <janburse@fastmail.fm>
Newsgroups	comp.lang.prolog
Subject	When do two Prolog terms marry? (Was: The issue with free speech)
Date	2024-10-14 19:15 +0200
Message-ID	<vejjj4$dlal$1@solani.org> (permalink)
References	<db8a6771-3e54-485b-b391-310658dd6f52n@googlegroups.com> <d9588b9c-edcc-4f8b-85d2-7487b5556798n@googlegroups.com> <ve6v8n$7df2$1@solani.org> <ve6vbr$7df2$2@solani.org> <ve718e$7ejh$1@solani.org>

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Now I was struggling giving this predicate
a better name. Namely variant_term bootstrapped
as follows:

variant_term(X, Y) :-
    subsumes_term(X, Y),
    subsumes_term(Y, X).

Why does it need a better name? Well because it
is not really the variant, as realized by
for example SWI-Prolog's (=@=):

For example I find:

?- variant_term(f(X,Y,Z,T), f(A,B,C,D)).
true.
?- variant_term(f(X,Y,Z,T), f(A,B,Z,D)).
true.
?- variant_term(f(A,Y,Z,T), f(A,B,Z,D)).
true.
?- variant_term(f(A,Y,Z,T), f(A,B,C,Z)).
fail.
?- variant_term(f(X,A,Z,T), f(A,B,Z,D)).
fail.

The first 3 test cases match what variant/2
usually does. But the last 2 test cases don't
match what variant/2 usually does.

So how can characterize the behaviour of
this weak variant. I came up with this observation:

- A weak variant takes has variables that appear
   in the left hand side and in the right hand side,
   i.e. common variables, only obtaining an identity
   relation.

- Othewise variables that are either specific to
   the right hand side or that are either specific
   to the left hand side, are associated by a
   bijection relation.

I came up with names like "twin", "sibling" for
this relation. But I got also inspired by the
fact that builtins:variant/2 from Scryer Prolog

leaves bindings. So looking for a name similar
like "unify", but only its weak variant and it
leaves a binding trace. My idea is to use "marry"!

Thread

Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-08-17 05:18 -0700
  Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-08-17 06:37 -0700
    Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-08-17 07:00 -0700
      Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-08-17 13:28 -0700
        Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-08-31 02:59 -0700
          Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-08-31 03:04 -0700
            Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-08-31 03:10 -0700
              Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-08-31 10:18 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-08-31 10:22 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-09 16:06 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-09 16:12 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-09 16:13 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-09 16:14 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-09 23:57 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-09 23:59 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-12 05:11 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-12 10:46 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-12 10:48 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-12 13:22 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-13 05:53 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-13 07:32 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-13 11:16 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-13 11:18 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-13 11:36 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-13 13:28 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-14 01:41 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-14 01:43 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-14 07:41 -0700
  Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <janburse@fastmail.fm> - 2022-10-15 14:30 +0200
    Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-19 07:42 -0700
      Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-19 07:50 -0700
      Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-19 07:51 -0700
        Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-19 07:52 -0700
          Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-19 18:55 -0700
            Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-19 18:58 -0700
              Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-19 19:46 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-25 05:55 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-25 05:59 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-25 08:36 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-25 10:53 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-26 07:01 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-10-26 07:02 -0700
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-11-14 14:21 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-11-14 14:31 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-11-17 06:08 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2022-11-17 06:21 -0800
  Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-11 12:45 -0800
    Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-11 12:52 -0800
      Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-11 14:24 -0800
        Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-13 01:56 -0800
          Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-13 01:58 -0800
            Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-13 01:59 -0800
            Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-13 02:01 -0800
              Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-13 04:49 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-16 15:03 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-16 15:07 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-17 00:49 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-01-17 03:22 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-02-27 03:08 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-02-27 03:08 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-02-27 10:31 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-02-27 10:33 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-02-27 16:05 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-03-01 09:01 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-03-01 09:02 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-03-02 04:06 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-03-02 04:08 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-03-08 01:45 -0800
                Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-03-08 01:47 -0800
  Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-03-18 05:55 -0700
    Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-03-18 05:56 -0700
      Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-03-18 06:01 -0700
        Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-03-18 06:06 -0700
  Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-05-13 06:36 -0700
    Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-05-13 06:41 -0700
  Re: Request for comments, Novacore the sequel to ISO modules Mostowski Collapse <bursejan@gmail.com> - 2023-05-21 03:54 -0700
    Differences among the "bomb" and "xbetween" (Was: Request for comments, Novacore the sequel to ISO modules) Mild Shock <janburse@fastmail.fm> - 2024-09-24 17:10 +0200
      The issue with free speech Mild Shock <janburse@fastmail.fm> - 2024-10-09 15:29 +0200
        failure of formal verification [software.imdea.org] (Was: The issue with free speech) Mild Shock <janburse@fastmail.fm> - 2024-11-06 09:33 +0100
          Re: failure of formal verification [software.imdea.org] (Was: The issue with free speech) Mild Shock <janburse@fastmail.fm> - 2024-11-06 09:35 +0100
            Re: failure of formal verification [software.imdea.org] (Was: The issue with free speech) Mild Shock <janburse@fastmail.fm> - 2024-11-06 09:37 +0100
      variant_term/2 is faster than variant/1 (Was: Request for comments, Novacore the sequel to ISO modules) Mild Shock <janburse@fastmail.fm> - 2024-10-12 22:02 +0200
        Re: variant_term/2 is faster than variant/1 (Was: Request for comments, Novacore the sequel to ISO modules) Mild Shock <janburse@fastmail.fm> - 2024-10-12 23:16 +0200
        Re: variant_term/2 is faster than variant/1 (Was: Request for comments, Novacore the sequel to ISO modules) Mild Shock <janburse@fastmail.fm> - 2024-10-12 23:34 +0200
          Re: variant_term/2 is faster than variant/1 (Was: Request for comments, Novacore the sequel to ISO modules) Mild Shock <janburse@fastmail.fm> - 2024-10-13 00:54 +0200
  Re: Request for comments, Novacore the sequel to ISO modules Mild Shock <bursejan@gmail.com> - 2023-07-29 04:51 -0700
    Re: Request for comments, Novacore the sequel to ISO modules Mild Shock <bursejan@gmail.com> - 2023-09-07 17:15 -0700
      Re: Request for comments, Novacore the sequel to ISO modules Mild Shock <janburse@fastmail.fm> - 2023-11-19 19:56 +0100
        Re: Request for comments, Novacore the sequel to ISO modules Mild Shock <janburse@fastmail.fm> - 2023-11-19 19:59 +0100
          Re: Request for comments, Novacore the sequel to ISO modules Mild Shock <janburse@fastmail.fm> - 2023-11-19 20:01 +0100
    New milestone float formatting [LoL] (Was: Request for comments, Novacore the sequel to ISO modules) Mild Shock <janburse@fastmail.fm> - 2024-07-28 14:32 +0200
      Re: New milestone float formatting [LoL] (Was: Request for comments, Novacore the sequel to ISO modules) Mild Shock <janburse@fastmail.fm> - 2024-07-28 14:38 +0200
        Re: New milestone float formatting [LoL] (Was: Request for comments, Novacore the sequel to ISO modules) Mild Shock <janburse@fastmail.fm> - 2024-07-28 16:42 +0200
          Re: Differences among the "bomb" and "xbetween" (Was: New milestone float formatting [LoL]) Mild Shock <janburse@fastmail.fm> - 2024-09-24 17:20 +0200
            New milestone time formatting (Was: Differences among the "bomb" and "xbetween") Mild Shock <janburse@fastmail.fm> - 2024-09-26 13:22 +0200
      More Prolog Improvement Proposals (PIPs) [PIP401 - PIP404] Mild Shock <janburse@fastmail.fm> - 2024-10-09 09:43 +0200
        Even More Prolog Improvement Proposals (PIPs) [PIP301 - PIP303] (Was: More Prolog Improvement Proposals (PIPs) [PIP401 - PIP404]) Mild Shock <janburse@fastmail.fm> - 2024-10-09 09:45 +0200
          Re: Even More Prolog Improvement Proposals (PIPs) [PIP301 - PIP303] (Was: More Prolog Improvement Proposals (PIPs) [PIP401 - PIP404]) Mild Shock <janburse@fastmail.fm> - 2024-10-09 10:00 +0200
            Re: Even More Prolog Improvement Proposals (PIPs) [PIP301 - PIP303] (Was: More Prolog Improvement Proposals (PIPs) [PIP401 - PIP404]) Mild Shock <janburse@fastmail.fm> - 2024-10-09 11:22 +0200
    A FFI for evaluable functions Mild Shock <janburse@fastmail.fm> - 2024-10-10 00:14 +0200
      Name resolution is a blackbox (Re: A FFI for evaluable functions) Mild Shock <janburse@fastmail.fm> - 2024-10-10 00:16 +0200
        plonk in discourse (Was: The issue with free speech) Mild Shock <janburse@fastmail.fm> - 2024-10-10 00:48 +0200
          When do two Prolog terms marry? (Was: The issue with free speech) Mild Shock <janburse@fastmail.fm> - 2024-10-14 19:15 +0200
            Re: When do two Prolog terms marry? (Was: The issue with free speech) Mild Shock <janburse@fastmail.fm> - 2024-10-14 19:22 +0200
            native implementation of variant/2 can be fast (Was: When do two Prolog terms marry?) Mild Shock <janburse@fastmail.fm> - 2024-10-15 01:35 +0200
      KISS principle pays off (Was: A FFI for evaluable functions) Mild Shock <janburse@fastmail.fm> - 2024-11-03 00:52 +0100
    Waste of EU money / bread and butter of statistics (Was: failure of formal verification [software.imdea.org]) Mild Shock <janburse@fastmail.fm> - 2024-11-06 09:51 +0100
      Re: Waste of EU money / bread and butter of statistics (Was: failure of formal verification [software.imdea.org]) Mild Shock <janburse@fastmail.fm> - 2024-11-06 10:09 +0100
      Re: Waste of EU money / bread and butter of statistics (Was: failure of formal verification [software.imdea.org]) Julio Di Egidio <julio@diegidio.name> - 2024-11-06 10:43 +0100
        SICStus Prolog is overrated (Was: Waste of EU money / bread and butter of statistics) Mild Shock <janburse@fastmail.fm> - 2024-11-06 12:57 +0100
          Crashing under its own bloath, Scryer Prolog (Was: SICStus Prolog is overrated) Mild Shock <janburse@fastmail.fm> - 2024-11-06 13:03 +0100
            “Luce,” which is Italian for “light.” (Was: Crashing under its own bloath, Scryer Prolog) Mild Shock <janburse@fastmail.fm> - 2024-11-06 13:12 +0100
              More Poisened Meat balls? [NIVIDIA & OpenAI] (Way: “Luce,” which is Italian for “light.”) Mild Shock <janburse@fastmail.fm> - 2024-11-06 13:33 +0100
                Re: More Poisened Meat balls? [NIVIDIA & OpenAI] (Way: “Luce,” which is Italian for “light.”) Julio Di Egidio <julio@diegidio.name> - 2024-11-06 14:17 +0100
    Not all Red-Black Trees are Okasaki (Was: Request for comments, Novacore the sequel to ISO modules) Mild Shock <janburse@fastmail.fm> - 2024-11-07 00:59 +0100
  Re: Request for comments, Novacore the sequel to ISO modules Mild Shock <bursejan@gmail.com> - 2023-11-19 10:54 -0800

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