From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: =?utf-8?Q?=C3=93scar_Fuentes?= Newsgroups: gmane.emacs.help Subject: Re: (*) -> 1 Date: Tue, 17 Jan 2023 19:11:20 +0100 Message-ID: <878ri1av5j.fsf@telefonica.net> References: <87sfg9kuya.fsf@web.de> <87bkmxkpzg.fsf@web.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="28751"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) To: help-gnu-emacs@gnu.org Cancel-Lock: sha1:uZF0K6UOQ5Gm7k7onwUNtw3l/Ss= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Tue Jan 17 19:11:55 2023 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1pHqR9-0007Fy-Lu for geh-help-gnu-emacs@m.gmane-mx.org; Tue, 17 Jan 2023 19:11:55 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pHqQo-0001Jz-EF; Tue, 17 Jan 2023 13:11:34 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pHqQm-0001JC-CD for help-gnu-emacs@gnu.org; Tue, 17 Jan 2023 13:11:32 -0500 Original-Received: from ciao.gmane.io ([116.202.254.214]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pHqQk-00031m-J1 for help-gnu-emacs@gnu.org; Tue, 17 Jan 2023 13:11:32 -0500 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1pHqQi-0006kP-Py for help-gnu-emacs@gnu.org; Tue, 17 Jan 2023 19:11:28 +0100 X-Injected-Via-Gmane: http://gmane.org/ Received-SPF: pass client-ip=116.202.254.214; envelope-from=geh-help-gnu-emacs@m.gmane-mx.org; helo=ciao.gmane.io X-Spam_score_int: -15 X-Spam_score: -1.6 X-Spam_bar: - X-Spam_report: (-1.6 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.25, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.help:142329 Archived-At: Michael Heerdegen writes: > Jean Louis writes: > >> (*) ➜ 1 >> (*) ➜ 1 >> >> We will get total of 2 Ferraris out of nothing. > > And with (concat) we get an empty string in the garage out of nothing. > > (*) and (concat) obviously are not useful in conjunction with Ferraris. > There is no interpretation in terms of Ferraris. > > We don't want to constrain math to things that have interpretations in > Ferrari collections. This is not about Mathematics, it is about notation, that means, convention, that means, convenience. In other programming languages an expression such as "+ 2" would yield a partially applied function: let f = + 2 f 5 -> 7 Lisp (or some implementations of it) went the route of "+ sums a list of numbers." That's fine, and in that sense having (+) -> 1 is reasonable, but there is nothing in Mathematics that says that it must be so instead of yielding partially applied function, or simply throwing an error message. Lisp's option is a consequence of its syntax (notation).