The topic of this talk are identities which are usually viewed as ``weak identities'', not to say ``formulase which are not even mathematical solid'', which are however found in many engineering or physics books. The examples are mostly taken from the area of time-frequency and Fourier Analysis. Distribution theory based on the Banach Gelfand Triple (SO,L2,SO') allows to provide a better understanding of these identities or claims.

FINALLY THIS TALK HAS NOT BEEN DELIVERED so far (Oct. 2018, Prague)