fixed zero element dispatch issue

Project.toml

@@ -1,7 +1,7 @@
 name = "Grassmann"
 uuid = "4df31cd9-4c27-5bea-88d0-e6a7146666d8"
 authors = ["Michael Reed"]
-version = "0.5.3"
+version = "0.5.4"
 
 [deps]
 AbstractTensors = "a8e43f4a-99b7-5565-8bf1-0165161caaea"
@@ -17,7 +17,7 @@ SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
 [compat]
 julia = "1"
 Reduce = "1.2"
-Leibniz = "0.0.4"
+Leibniz = "0.0.5"
 DirectSum = "0.5.3"
 AbstractTensors = "0.4.3"
 ComputedFieldTypes = "0.1"

src/Grassmann.jl

@@ -45,7 +45,7 @@ end
 
 using Leibniz
 import Leibniz: ∇, Δ, d # ∂
-export ∇, Δ, ∂, d, ↑, ↓
+export ∇, Δ, ∂, d, δ, ↑, ↓
 
 generate_products(:(Leibniz.Operator),:svec)
 for T ∈ (:(Simplex{V}),:(Chain{V}),:(MultiVector{V}))
@@ -80,6 +80,7 @@ end
 
 ∂(ω::T) where T<:TensorAlgebra = ω⋅Manifold(ω)(∇)
 d(ω::T) where T<:TensorAlgebra = Manifold(ω)(∇)∧ω
+δ(ω::T) where T<:TensorAlgebra = -∂(ω)
 
 function boundary_rank(t::T,d=gdims(t)) where T<:TensorAlgebra
     out = gdims(∂(t))

src/multivectors.jl

@@ -52,6 +52,7 @@ setindex!(m::Chain{V,G,T} where {V,G},k::T,i::Int) where T = (m.v[i] = k)
 Base.firstindex(m::Chain) = 1
 @pure Base.lastindex(m::Chain{V,G}) where {V,G} = binomial(ndims(V),G)
 @pure Base.length(m::Chain{V,G}) where {V,G} = binomial(ndims(V),G)
+Base.zero(::Chain{V,G,T}) where {V,G,T} = Chain{V,G}(zeros(svec(ndims(V),G,T)))
 
 function (m::Chain{V,G,T})(i::Integer) where {V,G,T}
     Simplex{V,G,SubManifold{V}(indexbasis(ndims(V),G)[i]),T}(m[i])