पूर्वकालैकसर्वजरत्पुराणनवकेवलाः समानाधिकरणेन

A case-inflected word denoting an action which naturally precedes in time (पूर्वकाल) and the words एक 'one', सर्व 'all' जरत 'old', पुराण 'ancient', नव 'new', and केवल 'only' are compounded with their co-relative case-inflected words which are in the same case with them and the resulting compound is तत्-पुरुष ।
The phrase सुप् सुपा is understood here, the whole sútra qualifying it.

Words which separately can be applied to many distinct and different objects, when they apply to one common object, are said to be in apposition (समानाधिकरणं) or abiding in a common substratum.

ln the present sútra the word-form púrva-kála, is not to be taken 1.1.68 but its significates; while of the rest एक &c., the very word-form is to be taken. A word denoting action which naturally precedes in time, is compounded with a word denoting action which naturally succeeds it. As, स्नातानुलिप्तः 'bathed and perfumed' कृष्टसमीकृतम् ' ploughed and levelled.' दग्धप्ररूढम् 'burnt and healed.' एकशाटी 'having one petticoat.' एकभिक्षा 'begging once in a day.' सर्वदेवाः 'All gods.' सर्वमनुष्याः 'all men.' जरद्धस्ती 'old elephant.' जरद्गृष्टिः 'an old cow.' जरद्वृत्तिः 'old occupation.' पुराणान्नम् 'old rice.' पुराणावसथम् 'an old habitation.' So नवान्नम्; नवावसथम्; केवलान्नम् 'only rice.'

Why do we say when they are in the same case? Observe एकस्याः शाटी 'one's petticoat.'
These and the subsequent compounds are Karmadháraya Compounds 1.2.42.