Full Idea
The 'structure' of an object tends to be characterised by Plato as something that is mathematically expressible.
Gist of Idea
Plato sees an object's structure as expressible in mathematics
Source
report of Plato (works [c.375 BCE]) by Kathrin Koslicki - The Structure of Objects 5.3
Book Reference
Koslicki,Kathrin: 'The Structure of Objects' [OUP 2008], p.98
A Reaction
This seems to be pure Pythagoreanism (see Idea 644). Plato is pursuing Pythagoras's research programme, of trying to find mathematics buried in every aspect of reality.
Related Idea
Idea 644 For Pythagoreans the entire universe is made of numbers [Pythagoras, by Aristotle]