In the question Is impulse response always differentiation of unit step response of a system? I've changed untagged to laplace-transform. It would be good, if someone who understands this post better, would check that tag and add other tags, if needed.

@Lord_Farin About your proposal. I am not sure whether it is better to keep (perhaps rename) congruences or to merge/synonimize this tag with modular-arithmetic.

That's why I have not upvoted your post. (At least not yet.)

But I certainly agree that it would be good to differentiate between several meanings of the word congruence used in mathematics.

@MartinSleziak Synonymizing it would be a bad idea, for it'll lead to mistagging. Perhaps modular-congruences could be admissible.

@Lord_Farin I don't like the sound of the phrase modular congruence. (It sounds as a congruence with some additional property.) I would prefer congruence-number-theory.