The absence of a 
at the end of a piece (in this case, Introduction) is quite a frequent phenomenon in Chopin's works. Generally, it means that the pedal should be pressed throughout the entire final fragment or that it should be gradually released (the so-called diminuendo pedal). According to us, in the discussed case, holding the pedal pressed to the end results in a very good sound effect; alternatively, the pedal can be gradually released throughout bar 31 to be pressed again (optionally) in bar 32.
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category imprint: Source & stylistic information
issues: No pedal release mark
notation: Pedalling