A1:
[:I[01],I[01]:] is SubSpace of [:R^1,R^1:]
by BORSUK_3:21;
the carrier of [:I[01],I[01]:] = [:(R^1 [.0,1.]),(R^1 [.0,1.]):]
by BORSUK_1:def 2, BORSUK_1:40;
hence
[:R^1,R^1:] | [:(R^1 [.0,1.]),(R^1 [.0,1.]):] = [:I[01],I[01]:]
by A1, TSEP_1:5, PRE_TOPC:8; verum