@acer ok ...

>> Also, a number (such as 11) applied to an argument evaluates to just 11 itself.

@acer that's not true (a real Bug?)

Download number_plus_argument.mwnumber_plus_argument.mw

@vv i requested an option to switch between both interpetations during parsing (like the option to show the multiplication dot or not, which seems not to work in Maple 2017 ... Tools --> Options --> Interface). IMO two different features need two different options.

@tomleslie sure, i am not a power user with Maple 2017 and i now the costs. But i will try to get an option to switch it off !

@tomleslie Any objection that i submit a software change request ?

@tomleslie @acer
Thank you both !
IMO this function feature is dangerous and it should be possible to disable it via Tools -> Options -> Interface !!

>> If you omit both an explicit multiplication symbol as well as an intervening space then in 2D Input (in Maple 2017)
     the second brackets will get parsed as an argument of a function call.

(i)  epsilon[3]b and epsilon[3]*b epsilon[3] b (with a blank) are the same in Maple 2017, indepently of the option

(ii) is there a change compared wirh Maple 2021 ?

(iii) is this feature (sin + cos)(x)  = sin(x) + cos(x) useable in scientfic (physics) papers ? (otherwise comparison difficult)

(iv) why not use braces for it: {sin + cos}(x) ? (because a space is invisible, it's diffcult to judge whether there is a blank or not)   

@tomleslie worksheet illustrating the problem

Implicit_Multiplication.mw
 

Download Implicit_Multiplication.mw