From what I've read so far, autosegmental phonology treats dissimilation as deletion of a feature and the result of the Obligatory Contour Principle. So how is the following case treated?
In Modern Greek, or sometime between Modern Greek and Ancient Greek, the first oral stop in a two voiceless oral stop sequence becomes the corresponding fricative.
It seems this is a dissimilation of
[-continuant, -sonorant, -voice] -> [+continuant] / _ [-continuant, -sonorant, -voice],
But I really don't know how to write this using autosegmental phonology.
*Relevant info: such consonant clusters in Greek are always inhomorganic - the places of articulation of the two consonants always differ. So there won't be cases like */t̪t̪/→/θt̪/.