Suppose Alice has a pair of shoes, worth $100. Bob steals one of the shoes and destroys it. Setting aside any special penalties, If Bob is caught and found liable, does he have to pay Alice back $50 for the one shoe, $100, because he has deprived her of use of both shoes, or some other amount?
The sefer Shaarei Daas on Bava Kama says that to destroy one shoe is not considered as damage to the other shoe, for the lack of one shoe does not destroy or maintain the viability of the second shoe. Rather, that one is unable to use the second shoe, but that is not called damage that one is culpable to pay damages for, rather the damager must pay for just the value of the one shoe that was destroyed.
In the Sefer Mishpatei Hatorah this issue is discussed at length and offers this possibility:
לפיכך היה מקום לומר בנידון דנן, שמכיון שפעולת הנזק היתה רק בנעל אחת, וההפסד שנגרם לנעל השניה שנשארה שלמה נעשה רק ממילא, לפיכך יתחייב המזיק לשלם רק לפי שווי הנעל היחידה שהזיק, דהיינו מחצית ממה שהיה שווה זוג הנעלים לפני פעולת הנזק.
Since the damage is only a grama, by destroying one shoe, memeilah the second shoe becomes unusable, it is only considered a grama, and for hezek, dina degarmi is patur, therefore, the mazik is only obligated to pay for the shoe that was destroyed.
See there for further discussion.
This issue is discussed as well in a Kovetz called Tzohar (צהר) volume 7 by Rav Yishaya Rottenberg the current Rav of the Gr"a shul in Bayit V'gan entitled מזיק נעל אחת
He quotes a haskama of the Shoel Umeishiv to a sefer called Divrei Geonei where this question is discussed.
As well as the sefer Shu"t Teshuras Shai (תרלט).
He should pay the price of a pair of shoes as by stealing one he has rendered the other uselss. Ex 22 says if a person steals they should restore double so 2 pairs of shoes. Ex 22.14 The onus is on the thief to make good Lev 19.11 says don't steal and don't deal falsely. By only offering to pay for one shoe you are dealing falsely as you know the man can't walk around in one shoe