Function eqDelta

src/compute-engine/rubi/rubi-utils.ts:588–591

u − v for binary EqQ/NeQ, or just u for the unary form (compare to 0).

(args: Json[], ctx: Ctx)

    if (json === 'False') return false;
    // SimplifyFlag and friends — not in steps mode
    return fail(`bare symbol condition '${json}'`);
  }
  if (!Array.isArray(json)) return fail('non-predicate condition');
  const [head, ...args] = json;
  if (head === 'And') return args.every((a) => evalCondition(a, ctx));
  if (head === 'Or') return args.some((a) => evalCondition(a, ctx));
  if (head === 'Not') return !evalCondition(args[0], ctx);