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.

Abū l-Ḥasan al-Nasawī, al-Ishbāʿ fī sharḥ al-shakl al-qaṭṭāʿ

Istanbul, Topkapı, Ahmet III 3464 · 206v

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