How do I make a \therefore in *plain tex* ?

[Steve Litt]

Thanks Yuri,

Your \input amssym solution works almost perfectly. The one downside is
that the dot triangle's size doesn't change with the math font size,
using either your \input fontch method or Philip's \scaled \magstep2
method. The size of the dot triangle is always the same. 

The font that controls the \therefore must be something other than what
Philip had on his list of enlarged fonts.

Does anybody know how to make the \therefore symbol from the amssym
package grow and shrink with the math font?

Thanks,

SteveT


Yuri Robbers said on Fri, 28 Apr 2023 10:11:26 +0100

>Hi Steve,
>
>Just use:
>
>\input amssym
>
>$\therefore$
>
>Good luck,
>Yuri 
>
>> On 28 Apr 2023, at 09:48, Steve Litt <slitt at troubleshooters.com>
>> wrote:
>> 
>> Hi all,
>> 
>> Right now I use the following:
>> 
>> \def\therefore{\bullet^\bullet\bullet\quad}
>> 
>> It kinda sorta works, but it's ugly.
>> 
>> Is there a better way to make a \therefore in Plain TeX?
>> 
>> Thanks,
>> 
>> SteveT
>> 
>> Steve Litt 
>> Autumn 2022 featured book: Thriving in Tough Times
>> http://www.troubleshooters.com/bookstore/thrive.htm  
>