> geqn seems to ignore part of explicit provided spaces "~" in the > above example (it seems to be the default spacing anyway). Is this > intended behaviour: "increase spacing only by the difference of > explicit provided space and default space"?
It seems so. I've compared the distances of the equations x = y + z and x~=~y~+~z in the original eqn2e.ps documentaion file `Typesetting Mathematics -- User's Guide (Second Edition), pageĀ 1 andĀ 2. The tilde characters before and after the equal sign cause no effect in the output; only the tilde characters before and after the `+' increase the spacing (by 0.6 PS points each, which is almost invisible). groff does exactly the same. Werner