let R be non empty RelStr ; :: thesis: for T being non empty 1-sorted
for p being Element of T holds the_value_of (R --> p) = p
let T be non empty 1-sorted ; :: thesis: for p being Element of T holds the_value_of (R --> p) = p
let p be Element of T; :: thesis: the_value_of (R --> p) = p
thus the_value_of (R --> p) = the_value_of the mapping of (R --> p) by Def10
.= the_value_of (the carrier of (R --> p) --> p) by Def7
.= p by Th2 ; :: thesis: verum