arXiv:2610.11973v1 Announce Type: new Abstract: Integrating over-the-air computation (AirComp) with non-orthogonal multiple access (NOMA) enables concurrent data aggregation and information transmission, but tightly couples computation accuracy with communication quality of service (QoS). This paper investigates a pinching-antenna-assisted uplink, where flexible pinching-antenna (PA) placement provides additional spatial degrees of freedom to manage this coupling. We minimize the AirComp mean-squared error (MSE) subject to NOMA QoS, transmit-power, and PA deployment constraints by jointly designing the AirComp transceiver, PA positions, and successive interference cancellation (SIC) order. Exploiting the recursive structure of uplink SIC, we establish an exact NOMA feasibility condition and derive an optimal SIC-ordering rule. These structural results eliminate the NOMA power variables and the combinatorial search over decoding orders, reducing the original problem to a continuous optimization problem. We then develop an iterative algorithm with optimal AirComp transmit-coefficient and receive-scaling updates and a feasibility-preserving majorization scheme for PA placement. The proposed algorithm preserves NOMA feasibility while generating a monotonically nonincreasing computation-MSE sequence. Numerical results demonstrate the computation-accuracy gains of jointly optimizing the AirComp transceiver and PA positions under NOMA QoS requirements.