theorem Th1: :: PAPDESAF:1

for OAS being OAffinSpace
for x being set holds
( ( x is Element of OAS implies x is Element of (Lambda OAS) ) & ( x is Element of (Lambda OAS) implies x is Element of OAS ) & ( x is Subset of OAS implies x is Subset of (Lambda OAS) ) & ( x is Subset of (Lambda OAS) implies x is Subset of OAS ) )