Lean4
/-- The one-preserving homomorphism including a single value
into a dependent family of values, as functions supported at a point.
This is the `OneHom` version of `Pi.mulSingle`. -/
@[to_additive /-- The zero-preserving homomorphism including a single value into a dependent family of values,
as functions supported at a point.
This is the `ZeroHom` version of `Pi.single`. -/
]
nonrec def mulSingle [∀ i, One <| f i] (i : I) : OneHom (f i) (∀ i, f i)
where
toFun := mulSingle i
map_one' := mulSingle_one i