I recently watched a film called
パパはわるものチャンピオン
and wondered whether the particle 'の' had been omitted between 'わるもの' and 'チャンピオン' in the film's title. Similarly, my mind turned to phrases like
東京大学
Is there a reason for the lack of 'の' between these sets of nouns? Thank you! (Sorry to waste time with what is probably a very simple question...)