let n be Nat; for X being object holds
( X is Subspace of REAL-NS n iff X is Subspace of TOP-REAL n )
let X be object ; ( X is Subspace of REAL-NS n iff X is Subspace of TOP-REAL n )
A1: the addF of (REAL-NS n) =
the addF of RLSStruct(# the carrier of (REAL-NS n), the ZeroF of (REAL-NS n), the addF of (REAL-NS n), the Mult of (REAL-NS n) #)
.=
the addF of RLSStruct(# the carrier of (TOP-REAL n), the ZeroF of (TOP-REAL n), the addF of (TOP-REAL n), the Mult of (TOP-REAL n) #)
by Th1
.=
the addF of (TOP-REAL n)
;
A2: the Mult of (REAL-NS n) =
the Mult of RLSStruct(# the carrier of (REAL-NS n), the ZeroF of (REAL-NS n), the addF of (REAL-NS n), the Mult of (REAL-NS n) #)
.=
the Mult of RLSStruct(# the carrier of (TOP-REAL n), the ZeroF of (TOP-REAL n), the addF of (TOP-REAL n), the Mult of (TOP-REAL n) #)
by Th1
.=
the Mult of (TOP-REAL n)
;
assume
X is Subspace of TOP-REAL n
; X is Subspace of REAL-NS n
then reconsider V = X as Subspace of TOP-REAL n ;
A5:
( the carrier of V c= the carrier of (TOP-REAL n) & 0. V = 0. (TOP-REAL n) & the addF of V = the addF of (TOP-REAL n) || the carrier of V & the Mult of V = the Mult of (TOP-REAL n) | [:REAL, the carrier of V:] )
by RLSUB_1:def 2;
A6:
the carrier of V c= the carrier of (REAL-NS n)
by A5, Th4;
0. V = 0. (REAL-NS n)
by A5, Th6;
hence
X is Subspace of REAL-NS n
by A1, A2, A5, A6, RLSUB_1:def 2; verum