Responsa for Shabbat 144:1
נתכוין להגביה את התלוש וחתך את המחובר פטור לחתוך את התלוש וחתך את המחובר רבא אמר פטור אביי אמר חייב רבא אמר פטור דהא לא נתכוון לחתיכה דאיסורא אביי אמר חייב דהא קמיכוין לחתיכה בעלמא
If one intended to lift up something detached, but cut off something attached [to the soil],<span class="x" onmousemove="('comment',' The latter is a forbidden act on the Sabbath. Rashi: e.g., if a knife fell down amidst growing corn, and whilst intending to lift it up one cut the corn. ');"><sup>1</sup></span> he is not culpable. [If he intended] to cut something detached, but cut something attached [instead],<span class="x" onmousemove="('comment',' R. Tam: e.g., he thought it was a detached bundle of corn, but after cutting it he discovered that it had been attached. ');"><sup>2</sup></span>
Maharach Or Zarua Responsa
R. Hayyim Eliezer recalls that one time, the winterhouse was once heated by a Gentile on the Sabbath, and his father refused to eat therein. R. Samuel of Falaise in the name of R. Yom Tov permitted one to dwell in a winterhouse that was warmed by a Gentile on the Sabbath. In our city, most of the people rely upon this decision and dwell in winterhouses that are warmed by Gentiles on the Sabbath.