EfficientNet function composition or Hadamard

In the page 3 of the paper of EfficientNet, there is a equation
$$mathcal{N} = bigodot_{i=1…s} mathcal{F}_{i}^{L_i} big(X_{langle H_i, W_i, C_i rangle}big)$$
where $mathcal{N}$ is the conv net and each $mathcal{F}_i^{L_i}$ is the $i$th-stage layer operator that has length $L_i$.

What I don’t understand is, what is this $odot$ in this equation? Does the author refer to the Hadamard product or does he refer to the function composition? He previously mentioned that $mathcal{N} = mathcal{F}_k odot … odot mathcal{F}_1 (X_1)$, where k is the depth of the net. So I thought it means that $odot$ is just function composition. But EfficientNet has skip connection. In the keras implementation it uses layers.merge.Multiply() so it can also means that the input data $X$ is multiplied with the transformed $mathcal{F}(X)$, and $odot$ maybe means the Hadamard product.

Does anyone knows the answer? Thanks.