理り論ろん上じょう

adverb

theoretically; in theory

Used as an adverb to describe something that is true according to theory, but may not be realized in practice.

• 理り論ろん上じょうは可か能のうだが、実じっ際さいには難むずかしい。

  It's possible in theory, but difficult in practice.

noun which may take the genitive case particle 'no'

theoretical

Used as a no-adjective to modify nouns, indicating that something is based on theory rather than practice.

• これは理り論ろん上じょうの問もん題だいに過すぎない。

  This is merely a theoretical problem.