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Abel's theorem in problems and solutions - School of Mathematics

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182 Problems <strong>of</strong> Chapter 2<br />

232). S<strong>in</strong>ce the value <strong>of</strong> at the <strong>in</strong>itial po<strong>in</strong>t <strong>of</strong> the curve can be<br />

chosen <strong>in</strong> different ways, we have exactly cont<strong>in</strong>uous curves, images<br />

<strong>of</strong> the curve under the mapp<strong>in</strong>g (the uniqueness may be<br />

lost only at the po<strong>in</strong>t but the curve does not pas through this<br />

po<strong>in</strong>t).<br />

Answer. The cont<strong>in</strong>uous images are the curves<br />

297. Let be an arbitrary curve jo<strong>in</strong><strong>in</strong>g the po<strong>in</strong>t 1 to an arbitrary<br />

po<strong>in</strong>t without cross<strong>in</strong>g the cut. From the solution <strong>of</strong> Problem 296, we<br />

obta<strong>in</strong> that if the value <strong>of</strong> the function at the <strong>in</strong>itial po<strong>in</strong>t <strong>of</strong> this curve is<br />

multiplied by then the values at the f<strong>in</strong>al po<strong>in</strong>t, def<strong>in</strong>ed by cont<strong>in</strong>uity,<br />

turns out to be multiplied by Hence<br />

Answer.<br />

298. Solv<strong>in</strong>g Problem 297 we have found that the branches <strong>of</strong><br />

the function are related each other <strong>in</strong> this way:<br />

The unique branch po<strong>in</strong>t <strong>of</strong> the function is the<br />

po<strong>in</strong>t Dur<strong>in</strong>g a simple turn around this po<strong>in</strong>t the argument <strong>of</strong> the<br />

function changes by (cf., 294), i.e., the value <strong>of</strong> the function<br />

varies by Consequently the scheme <strong>of</strong> the Riemann surface <strong>of</strong> the<br />

function has the form shown <strong>in</strong> Figure 71 (the Riemann surface for<br />

is shown <strong>in</strong> Figure 119).<br />

FIGURE 71<br />

299. Dur<strong>in</strong>g a turn around the po<strong>in</strong>t varies by<br />

<strong>and</strong> it does not change dur<strong>in</strong>g any other turn around the other po<strong>in</strong>ts<br />

(along sufficiently small circles). Dur<strong>in</strong>g a turn around the po<strong>in</strong>t<br />

thus changes by <strong>and</strong> it rema<strong>in</strong>s constant dur<strong>in</strong>g any other

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