PAL

Ptolemaeus Arabus et Latinus

_ (the underscore) is the placeholder for exactly one character.
% (the percent sign) is the placeholder for no, one or more than one character.
%% (two percent signs) is the placeholder for no, one or more than one character, but not for blank space (so that a search ends at word boundaries).

At the beginning and at the end, these placeholders are superfluous.

برهن ‘demonstrate’

Arabic

References: PH Morelon: I.2:5, 19:3
Translation of:
Greek: ἐπιδείκνυμι [PH Heiberg: I.2:5, 74:3-4]
Modern translations:
French: prouver [PH Morelon: I.2:5, 18:5]
German: beweisen [PH Nix: I.2:5, 75:4]