English
Define y(D) as the convolution of w(D) with φ, i.e., y(D)=w(D) ⋆ φ.
Русский
Определим y(D) как свертку w(D) и φ, то есть y(D)=w(D) ⋆ φ.
LaTeX
$$y(D, x) = (w(D) ⋆ φ)(x)$$
Lean4
/-- An auxiliary function to construct partitions of unity on finite-dimensional real vector spaces.
It is the convolution between a smooth function of integral `1` supported in the ball of radius `D`,
with the indicator function of the closed unit ball. Therefore, it is smooth, equal to `1` on the
ball of radius `1 - D`, with support equal to the ball of radius `1 + D`. -/
def y (D : ℝ) : E → ℝ :=
w D ⋆[lsmul ℝ ℝ, μ] φ