On the Eccentric Connectivity Polynomial of <span class="nowrap"><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.06579971pt" id="M1" height="11.8441pt" version="1.1" viewBox="-0.0657574 -11.7783 15.9607 11.8441" width="15.9607pt"><g transform="matrix(.017,0,0,-0.017,0,0)"><path id="g198-7" d="M896 662C863 643 826 624 783 624C682 624 539 680 429 680C328 680 253 659 202 616C163 583 138 537 138 484C138 399 208 349 283 349C396 349 466 417 492 554L472 555C436 442 385 379 286 379C234 379 179 410 179 491C179 578 257 634 382 634C475 634 622 574 731 574C796 574 862 610 907 647L896 662ZM657 568C577 499 520 440 477 341L463 310C368 277 286 233 247 186L260 171C320 211 380 237 437 256C349 77 281 31 184 31C124 31 83 59 78 94H80C87 83 101 81 109 81C137 81 153 104 153 131S130 180 103 180C68 180 43 154 43 111C43 34 123 0 192 0C335 0 469 75 546 282C599 291 640 293 661 294C653 267 650 244 650 224V206L709 226C706 235 706 245 706 252C706 271 706 289 714 312C758 333 786 368 786 387C786 403 775 409 763 409C744 409 712 391 685 352C644 351 604 345 564 337C595 433 622 506 671 554L657 568Z"/></g></svg>-</span>Sum of Connected Graphs

<div>The zig-zag polyhex nanotube <span class="nowrap"><svg height="12.5794pt" id="M222" style="vertical-align:-3.29107pt" version="1.1" viewbox="-0.0498162 -9.28833 74.4654 12.5794" width="74.4654pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M592 498C586 556 582 629 581 675H560C545 656 537 650 510 650H115C87 650 74 652 60 675H40C38 620 33 555 28 495H57C69 539 77 568 89 585C102 607 122 616 205 616H267V123C267 44 259 34 168 28V0H454V28C360 34 352 44 352 123V616H422C498 616 514 608 531 584C542 568 552 543 562 495L592 498Z"></path></g><g transform="matrix(.013,0,0,-0.013,8.021,0)"><path d="M716 650H478V622C549 617 570 605 575 566C579 535 582 493 582 401V326C582 161 537 40 393 40C269 40 205 133 205 294V521C205 611 213 617 291 622V650H33V622C111 615 120 611 120 521V272C120 154 148 80 208 34C252 0 309 -14 368 -14C434 -14 501 7 548 55C605 116 623 201 623 319V401C623 493 626 536 629 563C633 605 656 618 716 622V650Z"></path></g><g transform="matrix(.013,0,0,-0.013,17.589,0)"><path d="M729 650H468V622C546 615 554 610 554 527V365H213V527C213 610 221 616 297 622V650H38V622C120 616 128 611 128 527V123C128 39 120 34 40 28V0H303V28C221 34 213 40 213 123V322H554V123C554 39 546 34 460 28V0H728V28C647 34 639 39 639 123V527C639 610 647 615 729 622V650Z"></path></g><g transform="matrix(.013,0,0,-0.013,27.39,0)"><path d="M614 175C564 76 510 21 408 21C256 21 146 149 146 336C146 488 235 629 402 629C510 629 570 586 597 480L626 488C620 541 614 582 606 638C578 643 510 665 429 665C206 665 44 527 44 316C44 157 153 -15 402 -15C474 -15 558 5 586 11C604 45 629 119 643 165L614 175Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,36.171,3.132)"><path d="M141 347C171 480 264 541 327 570C364 587 403 599 436 605L429 641C389 634 339 622 300 609C191 570 37 458 37 239C37 86 126 -12 245 -12C367 -12 454 89 454 210C454 314 380 397 272 397C252 397 230 390 208 380L141 347ZM231 338C323 338 366 257 366 174C366 108 340 27 263 27C180 27 129 123 129 244C129 268 130 292 135 310C158 323 193 338 231 338Z"></path></g><g transform="matrix(.013,0,0,-0.013,41.118,0)"><path d="M290 -163V-135C183 -126 181 -122 181 -44V583C181 662 184 666 290 675V703H120V-163H290Z"></path></g><g transform="matrix(.013,0,0,-0.013,45.603,0)"><path d="M412 140C382 77 369 73 315 73H129L270 222C362 320 402 379 402 466C402 571 322 635 234 635C177 635 130 609 99 576L42 495L64 475C90 514 133 568 201 568C274 568 318 519 318 435C318 349 255 267 193 193C144 135 87 78 32 23V0H405C417 45 427 89 440 131L412 140Z"></path></g><g transform="matrix(.013,0,0,-0.013,51.843,0)"><path d="M480 416C480 431 465 448 438 448C388 448 312 383 252 330C217 299 188 273 155 237H153L257 680C262 700 263 712 253 712C240 712 183 684 97 674L92 648L126 647C166 646 172 645 163 606L23 -6L29 -12C51 -5 77 2 107 8C115 62 130 128 142 180C153 193 179 220 204 241C231 170 259 106 288 54C317 0 336 -12 358 -12C381 -12 423 2 477 80L460 100C434 74 408 54 398 54C385 54 374 65 351 107C326 154 282 241 263 299C296 332 351 377 403 377C424 377 436 372 445 368C449 366 456 368 462 375C472 386 480 402 480 416Z"></path></g><g transform="matrix(.013,0,0,-0.013,58.382,0)"><path d="M95 130C70 130 46 113 46 88C46 72 54 64 59 64C93 55 121 33 121 -3C121 -41 93 -68 44 -88L55 -117C117 -98 186 -56 186 22C186 91 131 130 95 130Z"></path></g><g transform="matrix(.013,0,0,-0.013,63.525,0)"><path d="M412 140C382 77 369 73 315 73H129L270 222C362 320 402 379 402 466C402 571 322 635 234 635C177 635 130 609 99 576L42 495L64 475C90 514 133 568 201 568C274 568 318 519 318 435C318 349 255 267 193 193C144 135 87 78 32 23V0H405C417 45 427 89 440 131L412 140Z"></path></g><g transform="matrix(.013,0,0,-0.013,69.765,0)"><path d="M226 -163V703H56V676C162 667 165 662 165 584V-43C165 -122 162 -126 56 -136V-163H226Z"></path></g></svg>.</span></div>

Complexity

fig3

Figure 3

Figure 3: On the Eccentric Connectivity Polynomial of <span class="nowrap"><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-0.06579971pt" id="M1" height="11.8441pt" version="1.1" viewBox="-0.0657574 -11.7783 15.9607 11.8441" width="15.9607pt"><g transform="matrix(.017,0,0,-0.017,0,0)"><path id="g198-7" d="M896 662C863 643 826 624 783 624C682 624 539 680 429 680C328 680 253 659 202 616C163 583 138 537 138 484C138 399 208 349 283 349C396 349 466 417 492 554L472 555C436 442 385 379 286 379C234 379 179 410 179 491C179 578 257 634 382 634C475 634 622 574 731 574C796 574 862 610 907 647L896 662ZM657 568C577 499 520 440 477 341L463 310C368 277 286 233 247 186L260 171C320 211 380 237 437 256C349 77 281 31 184 31C124 31 83 59 78 94H80C87 83 101 81 109 81C137 81 153 104 153 131S130 180 103 180C68 180 43 154 43 111C43 34 123 0 192 0C335 0 469 75 546 282C599 291 640 293 661 294C653 267 650 244 650 224V206L709 226C706 235 706 245 706 252C706 271 706 289 714 312C758 333 786 368 786 387C786 403 775 409 763 409C744 409 712 391 685 352C644 351 604 345 564 337C595 433 622 506 671 554L657 568Z"/></g></svg>-</span>Sum of Connected Graphs 

Complexity

On the Eccentric Connectivity Polynomial of -Sum of Connected Graphs

Figure 3