Mathematician here to clear something up:<br>x = 42 is a statement that you can logically imply that x is equal to 42 (via axiom).<br>x := 42 is the (probably more accurate as a programmer) statement that x is defined to be equal to 42 (via definition),(reply>), @Paul Newton Just use “:=” for assignment, following the Algol tradition.,(reply>), @Paul Newton there is an unfortunate lack of consensus. I think that since := is an accurate way to assign an unused variable, it should stand for malloc and then assign to a value in a new language and then = could potentially be used to modify it from there?<br>Of course, some might complain about that for being too complicated, and requiring an "unnecessary" key press upon first assignment (not that the latter point should matter at all),(reply>), So with the limited qwerty what symbol is better to represent assignment in languages that insist on symbols?<br>There's no explicit assignment notation in math to have parity with compsci. On general keyboards there is complete lack of math symbolism; no congruent|triple-bar(≡), no therefore(∴), or turnstiles(⊨),etc. Even then those example symbols are a stretch to mean assignment. There's cringey combo symbols for assignment that just increases complexity more than necessary they need to be(-&gt; , =&gt; , &lt;- , etc).<br>The popularity of Fortan's et al,  cursed us all until either keyboards inherently change, math academia has a concord on notation for assignment, or language designers stop blindly copying a flaw of tradition and new languages move to keywords(is, to, was) and old languages having aliases.,(reply>), @Kami it is, for the most part; the "truth values" aren't the same for "all interpretations" rather for the interpretations that we care about given the context. The real term is isomorphic (congruence is a type of isomorphism) denoted ≅. This describes when things are, via implication, identical given any properties which we care about (using this implies that they're not truly identical, usually because they aren't literally the exact same expression; they could be the same though),(reply>), @Benjamin Brady pretty sure congruent is logically equivalent. (As in the truth values are equal under all interpretation). If something logically follows it'd be just an implication.