How to get rid of the brackets appearing in non-commutative multiply?

I am getting output as

(-T1**T2**T3)**T4**T5


How to get rid of the brackets that are appearing in the output?

I want my output as

-T1**T2**T3**T4**T5

• 1. Please put any code you post in code blocks. Formatting help is automatically displayed for all new users when they edit a post. 2. It is not clear what you are asking. Give a complete example, include your input, explain what you want to achieve in plain terms. Ask a friend to read your question before submitting it. Make sure he understands it. Mar 25 '19 at 10:23

Non-commutative multiplication is by definition associative but not commutative. The minus sign in your formula, which is a regular multiplication with the number $$-1$$, blocks the automatic application of the associative property. You can see this by using FullForm:

(-T1 ** T2 ** T3) ** T4 ** T5 // FullForm


NonCommutativeMultiply[Times[-1, NonCommutativeMultiply[T1, T2, T3]], T4, T5]

To circumvent this problem you have to state the allowed transformation rules yourself, for example the associativity with regular multiplication by a number:

(-T1 ** T2 ** T3) ** T4 ** T5 /. (u_?NumericQ a_) ** b_ -> u (a ** b)


-T1 ** T2 ** T3 ** T4 ** T5