Mishnah Taharos 6:2: There are four cases of uncertain impurity which Rabbi Yehoshua declares impure and the Sages declare pure. How so? If an impure person stood [in a covered area, such as under a tree, constituting a "tent" or area of impurity,] and a pure person passed by; or a pure person stood [in a covered area] and an impure person passed by; or if something impure was in a private domain and [it was next to] something pure in the [adjacent] public domain; or if something pure was in the private domain and [it was next to] something impure in the [adjacent] public domain; if there is an uncertainty as to whether one touched [the impure object] or did not touch it, or whether it [i.e. the covered area] covered over [both the impure and the pure person at once] or did not cover over, or whether someone moved [the impure object, even indirectly] or did not move it; [in all these cases of uncertainty] Rabbi Yehoshua declares it impure, and the Sages declare it pure.

אַרְבָּעָה סְפֵקוֹת רַבִּי יְהוֹשֻׁעַ מְטַמֵּא וַחֲכָמִים מְטַהֲרִין. כֵּיצַד. הַטָּמֵא עוֹמֵד וְהַטָּהוֹר עוֹבֵר, הַטָּהוֹר עוֹמֵד וְהַטָּמֵא עוֹבֵר, הַטֻּמְאָה בִרְשׁוּת הַיָּחִיד וְטָהֳרָה בִרְשׁוּת הָרַבִּים, טָהֳרָה בִרְשׁוּת הַיָּחִיד וְטֻמְאָה בִרְשׁוּת הָרַבִּים, סָפֵק נָגַע סָפֵק לֹא נָגַע, סָפֵק הֶאֱהִיל סָפֵק לֹא הֶאֱהִיל, סָפֵק הִסִּיט סָפֵק לֹא הִסִּיט, רַבִּי יְהוֹשֻׁע מְטַמֵּא, וַחֲכָמִים מְטַהֲרִין:

Mishnah Taharos 6:3: A tree standing in a public domain which has something impure within it [i.e. among its branches], if someone climbed to its top, and it is uncertain whether he touched [the impurity] or did not touch it, its uncertainty is impure [i.e. such a case of uncertainty is ruled to be impure]. If someone put his hand into a hole containing something impure, and it is uncertain whether he touched it or did not touch it, its uncertainty is impure. A shop that was impure and open to the public domain, if there is an uncertainty as to whether someone entered it or did not enter it, its uncertainty is pure. If there is an uncertainty as to whether one touched [something impure inside a shop] or did not touch, its uncertainty is pure. If there were two shops, the one impure and one pure, and someone entered into one of them, and there is an uncertainty as to whether he entered into the impure one or entered into the pure one, its uncertainty is impure.

אִילָן שֶׁהוּא עוֹמֵד בִּרְשׁוּת הָרַבִּים וְהַטֻּמְאָה בְתוֹכוֹ, עָלָה לְרֹאשׁוֹ, סָפֵק נָגַע סָפֵק לֹא נָגַע, סְפֵקוֹ טָמֵא. הִכְנִיס יָדוֹ לְחוֹר שֶׁיֶּשׁ בּוֹ טֻמְאָה, סָפֵק נָגַע סָפֵק לֹא נָגַע, סְפֵקוֹ טָמֵא. חֲנוּת שֶׁהוּא טָמֵא וּפָתוּחַ לִרְשׁוּת הָרַבִּים, סָפֵק נִכְנַס סָפֵק לֹא נִכְנַס, סְפֵקוֹ טָהוֹר. סָפֵק נָגַע סָפֵק לֹא נָגַע, סְפֵקוֹ טָהוֹר. שְׁתֵּי חֲנֻיּוֹת, אֶחָד טָמֵא וְאֶחָד טָהוֹר, נִכְנַס לְאַחַד מֵהֶן, סָפֵק לַטָּמֵא נִכְנַס סָפֵק לַטָּהוֹר נִכְנַס, סְפֵקוֹ טָמֵא: