In functional analysis, an area of mathematics, the projective tensor product of two locally convex topological vector spaces is a natural topological vector space structure on their tensor product. Namely, given locally convex topological vector spaces X {\displaystyle X} and Y {\displaystyle Y} , the projective topology, or π-topology, on X ⊗ Y {\displaystyle X\otimes Y} is the strongest topology which makes X ⊗ Y {\displaystyle X\otimes Y} a locally convex topological vector space such that the canonical map ( x , y ) ↦ x ⊗ y {\displaystyle (x,y)\mapsto x\otimes y} (from X × Y {\displaystyle X\times Y} to X ⊗ Y {\displaystyle X\otimes Y} ) is continuous. When equipped with this topology, X ⊗ Y {\displaystyle X\otimes Y} is denoted X ⊗ π Y {\displaystyle X\otimes _{\pi }Y} and called the projective tensor product of X {\displaystyle X} and Y {\displaystyle Y} . It is a particular instance of a topological tensor product.