let V be ComplexLinearSpace; :: thesis: for V1 being Subset of V st V1 is linearly-closed & not V1 is empty holds
CLSStruct(# V1,(Zero_ V1,V),(Add_ V1,V),(Mult_ V1,V) #) is Subspace of V
let V1 be Subset of V; :: thesis: ( V1 is linearly-closed & not V1 is empty implies CLSStruct(# V1,(Zero_ V1,V),(Add_ V1,V),(Mult_ V1,V) #) is Subspace of V )
assume that
A1: V1 is linearly-closed and
A2: not V1 is empty ; :: thesis: CLSStruct(# V1,(Zero_ V1,V),(Add_ V1,V),(Mult_ V1,V) #) is Subspace of V
A3: Add_ V1,V = the addF of V || V1 by A1, Def8;
A4: Mult_ V1,V = the Mult of V | [:COMPLEX ,V1:] by A1, Def9;
Zero_ V1,V = 0. V by A1, A2, Def10;
hence CLSStruct(# V1,(Zero_ V1,V),(Add_ V1,V),(Mult_ V1,V) #) is Subspace of V by A2, A3, A4, CLVECT_1:44; :: thesis: verum