In order to avoid an excess of symbolism, I like to typeset displayed equations with some text replacing some connective, as in
(\forall x\in \mathbb{N}: \{1,\dots,x-1\} \subseteq B)
\rightarrow x\in B\quad \text{implies} \ B=\mathbb{N}.
As you can read, I had to insert some spaces manually in the code. To obtain pleasant-looking results, these spaces might depend, for instance, on the length of the formulas on each side (in this example, I needed a \quad before and a \ after the piece of text, but I'm not really happy with the result).
I found some related questions, like this one, but nothing exactly like this.
Is there any way of doing this automatically (and more correctly, for that matter)?
\textinclusion appears within a "math" line of a display, the spacing can be placed inside the\textstring. it's a bit more obvious there, and therefore may be easier to recognize and adjust. most of the "named" space commands work equally well in math or text. i can't think of any way to set this spacing automatically. – barbara beeton Dec 07 '15 at 17:15\text{ text }, does not add sufficient space for a displayed equation. – Pedro Sánchez Terraf Dec 08 '15 at 13:06\quadis always enough, nor the same spacing on both sides. Also, here I'm considering my example as an equation, but rather written in another style; so it should not be considered as text. – Pedro Sánchez Terraf Dec 08 '15 at 13:07\text{ text }. what i did mean is that\text{\qquad text\quad}or any other reasonable combination is possible. – barbara beeton Dec 08 '15 at 13:27